Tüm alıştırma soruları

2195 soru

Soru 1201Soru

A high-end audio equipment manufacturer evaluated the market value of a specialized manufacturing unit over a three-year period. In the first year, the unit's value increased by 25%25\%. In the second year, its value increased by 20%20\% relative to its value at the end of the first year. In the third year, its value decreased by 20%20\% relative to its value at the end of the second year. If the value of the unit at the end of the third year was $144,000\$144,000, what was its original value at the beginning of the first year?

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Cevap: $120,000\$120,000

Cevap

The original value at the beginning of the first year was $120,000\$120,000.
To determine the original value, find the overall multiplier for successive changes: an increase of 25%25\% (factor 1.251.25), an increase of 20%20\% (factor 1.201.20), and a decrease of 20%20\% (factor 0.800.80). The overall cumulative factor is 1.25×1.20×0.80=1.201.25 \times 1.20 \times 0.80 = 1.20. Dividing the final value of $144,000\$144,000 by 1.201.20 yields the correct initial value of $120,000\$120,000.

Adım Adım Çözüm

1
Express each year's percentage change as a growth/decay multiplier.
Year 1 factor =1+0.25=1.25=54= 1 + 0.25 = 1.25 = \frac{5}{4}. Year 2 factor =1+0.20=1.20=65= 1 + 0.20 = 1.20 = \frac{6}{5}. Year 3 factor =10.20=0.80=45= 1 - 0.20 = 0.80 = \frac{4}{5}.
Successive percentage changes must be calculated relative to each new intermediate value.
2
Calculate the cumulative multiplier over the three years.
Cumulative Multiplier =54×65×45=65=1.20= \frac{5}{4} \times \frac{6}{5} \times \frac{4}{5} = \frac{6}{5} = 1.20.
Multiplying individual period factors yields the net relationship between initial and final values.
3
Solve for the initial value V0V_0.
V0×1.20=144,000    V0=144,0001.20=120,000V_0 \times 1.20 = 144,000 \implies V_0 = \frac{144,000}{1.20} = 120,000.
Dividing the final value by the overall cumulative factor yields the original price.

Anahtar Kavram

Successive Percent Change and Base Multipliers
Tahmini Süre:1m 30s
Soru 1202Soru

A university admissions committee evaluates applicants from two distinct pools, Pool AA and Pool BB. In the first evaluation phase, accepting 40%40\% of the applicants from Pool AA and 60%60\% of the applicants from Pool BB results in a total of 180180 accepted students. In the second phase, accepting 70%70\% of the applicants from Pool AA and 30%30\% of the applicants from Pool BB results in a total of 210210 accepted students. What is the total number of applicants across both pools combined?

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Cevap: 380

Cevap

The total number of applicants across both pools combined is 380.
Translating the conditions into linear equations gives 0.40A+0.60B=1800.40A + 0.60B = 180 and 0.70A+0.30B=2100.70A + 0.30B = 210. Multiplying both equations to clear decimals yields 2A+3B=9002A + 3B = 900 and 7A+3B=21007A + 3B = 2100. Subtracting the first from the second eliminates BB, giving 5A=12005A = 1200, so A=240A = 240. Substituting A=240A = 240 into 2A+3B=9002A + 3B = 900 gives B=140B = 140. The sum A+B=240+140=380A + B = 240 + 140 = 380.

Adım Adım Çözüm

1
Set up a system of linear equations based on the percentage of accepted applicants from Pool A (AA) and Pool B (BB).
Equation 1: 0.40A+0.60B=1800.40A + 0.60B = 180; Equation 2: 0.70A+0.30B=2100.70A + 0.30B = 210.
Converting percentages to decimals forms linear equations relating the total applicants in each pool to the accepted totals.
2
Simplify the equations by multiplying by 10 and dividing by common factors.
Equation 1 becomes 2A+3B=9002A + 3B = 900; Equation 2 becomes 7A+3B=21007A + 3B = 2100.
Simplifying coefficients facilitates easier variable elimination.
3
Subtract the simplified Equation 1 from Equation 2 to eliminate BB and solve for AA.
(7A+3B)(2A+3B)=2100900    5A=1200    A=240(7A + 3B) - (2A + 3B) = 2100 - 900 \implies 5A = 1200 \implies A = 240.
Eliminating BB yields a single linear equation in AA.
4
Substitute A=240A = 240 back into 2A+3B=9002A + 3B = 900 to solve for BB.
2(240)+3B=900    480+3B=900    3B=420    B=1402(240) + 3B = 900 \implies 480 + 3B = 900 \implies 3B = 420 \implies B = 140.
Determines the population of Pool B.
5
Calculate the combined total of applicants from both pools.
A+B=240+140=380A + B = 240 + 140 = 380.
The question asks for the sum of applicants in both pools.

Anahtar Kavram

Solving Systems of Two-Variable Linear Equations using Elimination
Soru 1203Soru

For over a century, forest management in temperate biomes was dominated by the sustained-yield paradigm, an approach derived from nineteenth-century European silviculture that prioritized maximizing timber volume through the suppression of natural disturbance regimes. This paradigm presupposed that ecosystems inherently tend toward a static, highly predictable climax state, which could be maintained indefinitely through systematic human intervention. Under this framework, wildfire, insect outbreaks, and drought were categorized exclusively as exogenous shocks that disrupted timber productivity and demanded immediate eradication.

However, emerging empirical research in historical ecology has fundamentally undermined the theoretical foundations of sustained-yield silviculture. Recent dendrochronological and paleoecological analyses reveal that pre-industrial temperate forests were not static monocultures, but rather dynamic mosaics continuously shaped by low-intensity, recurrent disturbances. Far from destabilizing these ecosystems, periodic fires and localized pest infestations cleared understory biomass, facilitated nutrient cycling, and maintained structural heterogeneity essential for long-term biodiversity. By systematically suppressing these natural disturbance vectors throughout the twentieth century, management practices unintentionally fostered uniform, dense stands susceptible to catastrophic, landscape-scale collapses when environmental stressors inevitably surpassed historical thresholds.

To address these legacy vulnerabilities, contemporary conservation biologists advocate transitioning toward adaptive disturbance-based management. This model seeks to mirror historical disturbance regimes by incorporating prescribed burning and selective thinning, thereby re-establishing structural complexity and ecological flexibility. Critics contend that such approaches compromise immediate commercial timber yields and introduce operational unpredictability into forestry markets. Nevertheless, proponents maintain that prioritizing ecological resilience over short-term volumetric optimization offers the only viable safeguard against climate-induced regime shifts.

Which of the following best describes the function of the second paragraph in relation to the passage as a whole?

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Cevap: It introduces empirical findings that challenge the foundational assumptions of the tradition described in the first paragraph and details the negative consequences of that tradition.

Cevap

The second paragraph functions to introduce empirical findings that challenge the foundational assumptions of the traditional model introduced in the first paragraph and to detail the negative ecological consequences resulting from that traditional model.
The correct answer accurately describes the structural role of the second paragraph. The second paragraph opens with a clear contrastive pivot ('However') to introduce empirical research from historical ecology that refutes the static premise of the sustained-yield paradigm detailed in the first paragraph. It then explains how suppressing natural disturbances led to dense, uniform forest stands susceptible to catastrophic collapses.

Adım Adım Çözüm

1
Analyze the structural role of Paragraph 1
Paragraph 1 establishes the baseline context: the traditional 'sustained-yield' silviculture paradigm and its assumption that forests reach a static climax state best maintained by eliminating natural disturbances.
Understanding the context of Paragraph 1 is necessary to determine how Paragraph 2 responds to or develops it.
2
Analyze the structural pivot and body of Paragraph 2
Paragraph 2 begins with a contrastive marker ('However') and cites empirical research (dendrochronological/paleoecological) showing pre-industrial forests were dynamic mosaics maintained by disturbance. It concludes by explaining how twentieth-century fire suppression caused uniform stands vulnerable to catastrophic collapse.
This establishes that Paragraph 2 directly refutes the theoretical premise of Paragraph 1 and explains the harmful outcome of applying that premise.
3
Evaluate how Paragraph 2 connects to Paragraph 3 and the overall passage movement
Paragraph 2 acts as the bridge between the flawed traditional view (Paragraph 1) and the proposed modern alternative (Paragraph 3), supplying the scientific justification for abandoning the old approach.
Matching this overall rhetorical trajectory reveals that the correct option must state that Paragraph 2 challenges the first paragraph's assumptions and highlights its unintended negative consequences.

Anahtar Kavram

Determining Paragraph Function and Structural Role
Soru 1204Soru

Passage:
For decades, oceanographers posited that primary biological productivity in oceanic oxygen minimum zones (OMZs) was strictly bottlenecked by the availability of fixed nitrogen, which is rapidly depleted through microbial denitrification. According to classical biogeochemical models, as oxygen levels decline, denitrifying bacteria convert bioavailable nitrate into inert dinitrogen gas, creating an energetic desert incapable of supporting complex planktonic communities. However, recent genomic sequencing of microbial assemblages in the Eastern Tropical South Pacific OMZ has challenged this long-standing paradigm. Researchers discovered abundant populations of hitherto uncharacterized chemolithoautotrophic bacteria that couple anaerobic ammonium oxidation with the reduction of trivalent iron species. Rather than acting purely as nutrient sinks, these OMZs host self-sustaining metabolic networks wherein iron cycling continuously replenishes bioavailable nitrogen intermediates. Consequently, while traditional frameworks viewed oxygen depletion exclusively as a driver of marine ecological degradation, the emerging perspective recognizes OMZs as dynamic biogeochemical engines that maintain regional primary productivity despite extreme hypoxia. By demonstrating that microbial metabolic plasticity buffers nitrogen loss, these findings necessitate a substantial revision of global oceanic carbon and nitrogen budget models.

Which of the following best expresses the primary purpose of the passage?

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Cevap: present recent scientific findings that challenge a long-held model of oceanic nutrient depletion and propose a revised ecological perspective.

Cevap

The primary purpose of the passage is to present recent scientific findings that challenge a long-held model of oceanic nutrient depletion and propose a revised ecological perspective.
The passage opens by describing a long-standing traditional view regarding oxygen minimum zones and nutrient depletion, introduces recent genomic research showing a newly discovered metabolic pathway using the pivot 'However', and concludes by explaining how these findings require a substantial revision of classical biogeochemical models. The option stating that the passage presents recent scientific findings that challenge a long-held model accurately captures this overarching structure and main objective.

Adım Adım Çözüm

1
Analyze the structural organization of the passage.
The first two sentences outline a traditional scientific consensus (oceanic OMZs are nutrient deserts due to nitrogen depletion).
Establishing the starting context reveals what baseline idea is being addressed.
2
Identify key structural pivots and shifts in tone.
The transition word 'However' introduces new genomic discoveries regarding chemolithoautotrophic bacteria and iron cycling.
Pivots signal the main point or counter-thesis the author intends to highlight.
3
Synthesize the conclusion and overall rhetorical goal.
The final sentences explain how these findings revise classical models by showing OMZs as dynamic engines maintaining productivity.
Combining the new evidence with its broader theoretical implication provides the complete primary purpose.

Anahtar Kavram

Identifying Primary Purpose and Main Idea
Soru 1205Soru

In City X, municipal health officials observed that residents living in neighborhoods with a high density of full-service grocery stores report significantly lower rates of cardiovascular disease than residents in neighborhoods served primarily by fast-food outlets and convenience stores. To reduce the citywide incidence of cardiovascular disease, the city council proposes offering tax incentives to attract full-service grocery stores to underserved neighborhoods. The council reasons that increasing physical access to fresh produce will prompt residents to adopt healthier diets, thereby directly lowering their risk of cardiovascular illness.

Which of the following, if true, provides the strongest support for the city council's reasoning?

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Cevap: Individuals who maintain healthy diets are no more likely to choose to live in neighborhoods with full-service grocery stores than are individuals with poor dietary habits.

Cevap

The correct response is the statement establishing that individuals with healthy diets are no more likely to move to neighborhoods with full-service grocery stores than those with poor diets.
The city council's argument relies on a causal claim: increasing physical access to fresh produce will cause residents to adopt healthier diets and lower their risk of cardiovascular disease. The evidence provided is a mere correlation between grocery store density and lower disease rates. A key vulnerability of correlation-to-causation reasoning is the possibility of self-selection bias—specifically, that health-conscious people actively choose to live in areas near full-service grocery stores. By confirming that individuals with healthy diets are no more likely to relocate to these neighborhoods than individuals with poor diets, the correct answer rules out self-selection bias, thereby substantially strengthening the likelihood that the stores themselves positively influence resident health.

Adım Adım Çözüm

1
Deconstruct the argument structure into premises, proposed action, and core conclusion.
Premise: Grocery store density correlates with lower cardiovascular disease. Action: Provide tax incentives for grocery stores in underserved areas. Conclusion: Increased physical access will cause healthier diets and directly reduce cardiovascular disease risk.
Identifying the logic gap between correlation (store location and health) and causation (store access causing health improvement) is crucial for strengthening the argument.
2
Identify potential vulnerabilities and unstated assumptions in the causal leap.
The main vulnerability is reverse causality or self-selection bias: perhaps health-conscious people self-select into neighborhoods with grocery stores, rather than the stores causing residents to become healthy.
To strengthen a causal argument based on observational correlation, one must rule out alternative explanations or confounding variables.
3
Evaluate the options to find the one that addresses the self-selection vulnerability.
The option stating that healthy eaters do not preferentially move to grocery-rich neighborhoods eliminates self-selection bias, ensuring the correlation is driven by the environment rather than residential preference.
Ruling out a major confounding variable directly strengthens the author's causal claim.

Anahtar Kavram

Strengthening Causal Arguments by Eliminating Confounding Variables / Reverse Causality
Soru 1206Soru

A committee of 44 delegates is to be selected from a group of 55 diplomats from Country X and 44 diplomats from Country Y. If 11 specific diplomat from Country X and 11 specific diplomat from Country Y cannot both serve on the committee together, how many different 44-member committees can be formed?

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Cevap: 105

Cevap

105
To find the number of valid 4-member committees, calculate the total combinations of choosing 4 delegates from 9 diplomats, (94)=126\binom{9}{4} = 126. Then subtract the restricted outcomes where both specific diplomats are selected. If both specific diplomats are included, the remaining 2 positions on the committee must be chosen from the remaining 7 diplomats, which can be done in (72)=21\binom{7}{2} = 21 ways. Subtracting these invalid outcomes gives 12621=105126 - 21 = 105.

Adım Adım Çözüm

1
Calculate the total number of ways to choose 4 delegates from the total pool of 9 diplomats without any restrictions.
\binom{9}{4} = \frac{9 \times 8 \times 7 \times 6}{4 \times 3 \times 2 \times 1} = 126
The total pool consists of 5 diplomats from Country X + 4 diplomats from Country Y = 9 diplomats.
2
Calculate the number of invalid committee selections where both specific diplomats are selected together.
\binom{7}{2} = \frac{7 \times 6}{2 \times 1} = 21
If the 2 specific diplomats are both placed on the committee, 2 remaining seats must be filled from the remaining 7 diplomats.
3
Subtract the invalid combinations from the total combinations to find the number of valid committees.
126 - 21 = 105
Complementary counting gives the number of committees where both specific diplomats do not serve together.

Anahtar Kavram

Combinations with restrictions using complementary counting
Tahmini Süre:2m 0s
Soru 1207Soru

In nineteenth-century European architectural history, structural engineers encountered widespread opposition from academic purists regarding the integration of cast iron into public building frameworks. Theoretical detractors argued that cast iron lacked the tensile ductility of wrought iron, rendering structural elements dangerously vulnerable to sudden brittle fracture under asymmetric thermal expansion or localized impact. However, recent historical analysis of municipal treasury records and engineering logs reveals that municipal planning committees between 1840 and 1865 systematically selected cast iron for urban transit terminals and multi-tiered commercial halls. Contrary to the long-held assumption that this preference stemmed from technical negligence, municipal authorities prioritized cast iron primarily because of its exceptional compressive strength when enclosed within masonry piers, as well as its considerably lower founding and casting costs. Furthermore, while structural theorist Henri Dupin famously contended in an 1848 treatise that unreinforced cast-iron columns posed unacceptable structural risks in public edifices unless bound by exterior wrought-iron tension straps, municipal building inspectors consistently granted regulatory exemptions to single-story exhibition galleries. These exemptions were contingent upon foundational footings being anchored directly into solid bedrock substrates rather than unstable alluvial deposits. This distinct regulatory loophole allowed suburban commercial developers to bypass the expensive metallurgical stress testing normally compulsory for urban high-rise construction, accelerating suburban commercial expansion despite ongoing academic warnings.

According to the passage, municipal building inspectors granted regulatory exemptions regarding cast-iron reinforcement in single-story exhibition galleries under which of the following conditions?

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Cevap: The structural bases of the edifices were established directly upon firm geological rock rather than loose river sediment.

Cevap

The regulatory exemptions were granted on the condition that the structural bases of the edifices were established directly upon firm geological rock rather than loose river sediment.
The correct answer accurately paraphrases the explicit condition stated in the passage. The text explicitly notes that regulatory exemptions granted to single-story exhibition galleries were contingent upon foundational footings being anchored directly into solid bedrock substrates rather than unstable alluvial deposits. The correct option captures this exact relationship using equivalent terms: 'structural bases' for foundational footings, 'firm geological rock' for solid bedrock substrates, and 'loose river sediment' for alluvial deposits.

Adım Adım Çözüm

1
Locate the targeted detail in the passage
Identified the sentence discussing regulatory exemptions for single-story exhibition galleries near the end of the passage.
Direct factual retrieval requires locating the precise textual reference addressing the specific condition stated in the prompt.
2
Analyze explicit passage evidence
The text states: 'These exemptions were contingent upon foundational footings being anchored directly into solid bedrock substrates rather than unstable alluvial deposits.'
Understanding the exact factual scope ensures proper evaluation of paraphrased answer choices.
3
Match explicit evidence to semantic equivalents in options
'Foundational footings' translates to 'structural bases', 'anchored directly into solid bedrock substrates' translates to 'established directly upon firm geological rock', and 'unstable alluvial deposits' translates to 'loose river sediment'.
Correct GMAT Reading Comprehension answers frequently rely on precise semantic paraphrasing rather than verbatim word matching.

Anahtar Kavram

Direct Factual Retrieval and Semantic Paraphrasing
Soru 1208Soru

Passage:
For several decades, scholars analyzing Bronze Age Eurasian population dynamics relied almost exclusively on strontium isotope analysis of human dental enamel, an analytical framework that infers geographic mobility by matching isotopic ratios in bone to localized geological baselines. While early proponents heralded strontium profiling as an objective empirical counterweight to speculative archaeological typologies, recent bioarchaeology has exposed structural limitations in the methodology. Specifically, diagenetic contamination and localized variations in dietary soil intake can skew strontium signatures, causing sedentary individuals consuming imported grain to appear deceptively mobile, or conversely, masking long-distance migration among populations reliant on uniform maritime diets.

In response to these diagnostic vulnerabilities, a new cadre of geneticists has championed high-throughput ancient DNA (aDNA) sequencing as a definitive replacement for isotopic provenance markers. Proponents of this genomic turn contend that genome-wide single nucleotide polymorphism (SNP) array data provides an unadulterated lineage trajectory, rendering biogeochemical proxies obsolete. Yet, this totalizing dismissal of isotopic data is uncomfortably premature. Although genomic sequencing unequivocally elucidates deep ancestral affiliations across millennial timescales, it remains remarkably insensitive to short-range, single-generation geographic movements that leave no immediate genetic trace in local gene pools. A micro-regional pastoralist seasonal migration, for instance, escapes genomic detection entirely if intermarriage does not occur. Thus, while genomic methods undeniably refine our understanding of macro-scale population shifts, discarding strontium analysis altogether ignores its unique capacity to capture non-reproductive physical transit within an individual's lifetime. A truly robust historical synthesis demands a calibrated integration of both methodologies rather than the uncritical substitution of one empirical paradigm for another.

Based on the passage, the author's stance toward the position held by the "new cadre of geneticists" is best described as which of the following?

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Cevap: Guarded recognition of their contributions to macro-scale analysis, combined with skepticism regarding their complete abandonment of isotopic data.

Cevap

The author's stance is best described as guarded recognition of the geneticists' contributions to macro-scale analysis, combined with skepticism regarding their complete abandonment of isotopic data.
The author exhibits a qualified attitude toward the geneticists' paradigm. On one hand, the author acknowledges that genomic sequencing 'unequivocally elucidates deep ancestral affiliations' and 'undeniably refines our understanding of macro-scale population shifts.' On the other hand, the author explicitly characterizes their total rejection of strontium analysis as 'uncomfortably premature' and calls for a 'calibrated integration of both methodologies.' Thus, the option expressing guarded recognition paired with skepticism regarding the complete abandonment of isotopic data perfectly reflects this nuanced stance.

Adım Adım Çözüm

1
Identify the author's structural pivots and tone markers regarding the geneticists.
The author introduces the geneticists' view that ancient DNA renders isotopic markers obsolete, then immediately inserts a contrastive pivot: 'Yet, this totalizing dismissal of isotopic data is uncomfortably premature.'
Tracking pivot words reveals where the author shifts from summarizing a secondary perspective to evaluating it.
2
Analyze the qualified concessions made by the author toward genomic sequencing.
The author grants that genomic sequencing 'unequivocally elucidates deep ancestral affiliations' and 'undeniably refines our understanding of macro-scale population shifts.'
This establishes that the author respects the utility of ancient DNA within its proper scope rather than rejecting it outright.
3
Synthesize the concessions and critiques to determine the overall tone.
The author Advocates for a 'calibrated integration of both methodologies' and opposes 'uncritical substitution,' revealing a measured, qualified stance.
A balanced tone combining partial agreement with targeted skepticism fits 'guarded recognition combined with skepticism.'

Anahtar Kavram

Author Attitude and Tone Inferences
Soru 1209Soru

A financial consultancy firm consists of two divisions: Risk Management and Wealth Advisory. The 4040 analysts in the Risk Management division earn an average annual bonus of $15,000\$15,000, while the analysts in the Wealth Advisory division earn an average annual bonus of $25,000\$25,000. If the average annual bonus across all analysts in both divisions combined is $21,000\$21,000, how many analysts work in the Wealth Advisory division?

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Cevap: 60

Cevap

The Wealth Advisory division has 60 analysts.
The combined mean of two sets is closer to the mean of the larger set. Using the distance-ratio rule for weighted averages, the ratio of the number of Risk Management analysts to Wealth Advisory analysts is inversely proportional to their distances from the combined mean: Ratio=25,00021,00021,00015,000=4,0006,000=23\text{Ratio} = \frac{25,000 - 21,000}{21,000 - 15,000} = \frac{4,000}{6,000} = \frac{2}{3}. Given that there are 40 analysts in Risk Management (representing 2 parts), each part equals 20 analysts. Therefore, the 3 parts for Wealth Advisory equal 3×20=603 \times 20 = 60 analysts.

Adım Adım Çözüm

1
Set up the weighted average equation with NN representing the number of analysts in the Wealth Advisory division.
Total bonus for Risk Management = 40×15,000=600,00040 \times 15,000 = 600,000. Total bonus for Wealth Advisory = N×25,000N \times 25,000. Total analysts = 40+N40 + N.
The combined mean is equal to the sum of all individual values divided by the total number of items.
2
Formulate the combined average equation and clear the fraction.
\frac{600,000 + 25,000N}{40 + N} = 21,000 \implies 600,000 + 25,000N = 21,000(40 + N)
Equate the weighted average expression to the given overall average of $21,000\$21,000.
3
Expand and solve the linear equation for NN.
600,000 + 25,000N = 840,000 + 21,000N \implies 4,000N = 240,000 \implies N = 60
Isolate the variable NN to find the exact number of analysts in Wealth Advisory.

Anahtar Kavram

Weighted Average and Combined Sets
Tahmini Süre:1m 30s
Soru 1210Soru

A cybersecurity firm must select a 4-tool diagnostic suite from a pool of 6 network scanners and 4 code analyzers. If the suite must contain at least 1 network scanner and at least 1 code analyzer, how many different 4-tool suites can be selected?

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Cevap: 194

Cevap

The total number of different 4-tool suites that can be selected is 194.
The total number of ways to select any 4 tools from the pool of 10 is (104)=210\binom{10}{4} = 210. The only selections that violate the requirement of having at least one tool of each type are choosing 4 scanners and 0 analyzers ((64)=15\binom{6}{4} = 15 ways) or 0 scanners and 4 analyzers ((44)=1\binom{4}{4} = 1 way). Subtracting these 16 invalid outcomes from the total gives 21016=194210 - 16 = 194 valid 4-tool suites.

Adım Adım Çözüm

1
Calculate the total unconstrained selections
210
There are 6+4=106 + 4 = 10 total tools, and 4 must be chosen. (104)=10×9×8×74×3×2×1=210\binom{10}{4} = \frac{10 \times 9 \times 8 \times 7}{4 \times 3 \times 2 \times 1} = 210.
2
Determine the number of invalid combinations violating the constraint
16 invalid combinations
The constraint requires at least 1 scanner and 1 analyzer. Invalid suites consist entirely of scanners ((64)=15\binom{6}{4} = 15) or entirely of analyzers ((44)=1\binom{4}{4} = 1).
3
Apply complementary counting to find the valid combinations
194 valid combinations
Subtract the invalid combinations from total unconstrained combinations: 210(15+1)=194210 - (15 + 1) = 194.

Anahtar Kavram

Combinations with Group Selections and Complementary Counting
Soru 1211Soru

For over half a century, evolutionary biologists held that the emergence of eukaryotic cells was driven primarily by an ancestral phagotrophic host cell engulfing an aerobic bacterium—the classical mitochondria-first model. Recently, however, proponents of the 'hydrogen hypothesis' have posited a syntrophic metabolic relationship as the initial catalyst, arguing that eukaryotes arose from an obligate association between a hydrogen-dependent methanogenic archaeon and a hydrogen-producing eubacterium. While some researchers dismiss the hydrogen hypothesis as an unnecessary complication of an established endosymbiotic framework, its advocates contend it elegantly resolves the bioenergetic paradoxes inherent in assuming a complex host existed prior to organelle acquisition.

Nevertheless, this revisionist paradigm is not without its own structural vulnerabilities. In placing metabolic interdependence prior to cellular internalization, the hydrogen hypothesis relies heavily on hypothetical geochemical niches for which direct Precambrian geological evidence remains stubbornly sparse. Furthermore, its proponents frequently downplay the formidable thermodynamic barriers preventing stable syntrophy between unspecialized prokaryotes without pre-existing structural adaptations. Consequently, while the hydrogen hypothesis helpfully challenges the unwarranted assumption that host complexity preceded endosymbiosis, treating it as a definitive replacement for classical models is premature. The hypothesis is best viewed not as an established doctrine, but as a compelling conceptual catalyst that exposes the empirical lacunae of current origin-of-life models.

Based on the passage, the author's attitude toward the 'hydrogen hypothesis' can best be described as which of the following?

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Cevap: measured recognition of its intellectual utility in questioning existing assumptions, combined with skepticism regarding its current empirical support

Cevap

The author exhibits a measured appreciation for the hypothesis's conceptual value alongside explicit reservations about its empirical and theoretical gaps.
The correct answer accurately reflects the author's balanced, nuanced stance. The author credits the hydrogen hypothesis with 'helpfully' challenging conventional assumptions and terms it a 'compelling conceptual catalyst', while simultaneously cautioning that geological evidence is 'stubbornly sparse' and that adopting it as a definitive replacement would be 'premature'.

Adım Adım Çözüm

1
Identify the author's explicit evaluations of the hydrogen hypothesis throughout the text.
In paragraph 2, the author notes that the hypothesis 'helpfully challenges the unwarranted assumption' but states that treating it as a replacement is 'premature' due to 'stubbornly sparse' evidence and 'formidable thermodynamic barriers'.
Tracking tone markers (e.g., 'helpfully challenges', 'premature', 'compelling conceptual catalyst') isolates the author's exact perspective.
2
Distinguish the author's voice from secondary perspectives cited in the passage.
The dismissal of the hypothesis as an 'unnecessary complication' belongs to 'some researchers', not the author.
Preventing perspective misattribution ensures opposing scholarly views are not mistaken for the author's own stance.
3
Select the option that reflects a balanced, qualified stance matching 'compelling conceptual catalyst' paired with 'premature'.
The statement describing measured recognition of intellectual utility alongside skepticism regarding empirical support reflects this balanced tone.
GMAT Reading Comprehension tone questions require identifying nuanced, moderate positions over extreme or one-sided claims.

Anahtar Kavram

Author Attitude and Tone Inferences
Soru 1212Soru

Read the following statement from an economic history of Eastern European agrarian systems:

"Although late nineteenth-century historians routinely attributed the rapid decline of peasant landholding in the Lower Danube basin exclusively to rising Ottoman taxation, recent econometric reassessments of regional court registries reveal that smallholders who retained access to communal pastureland managed to offset tax increases, whereas those reliant solely on arable plots were forced into tenant contracts even during years of stable tax levies."

Based on the sentence above, which of the following is most strongly supported regarding smallholders in the Lower Danube basin during the late nineteenth century?

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Cevap: Smallholders lacking access to communal pastureland could be forced into tenancy by factors other than tax increases.

Cevap

Smallholders lacking access to communal pastureland could be forced into tenancy by factors other than tax increases.
The sentence states that smallholders reliant solely on arable plots (i.e., those without pastureland access) were forced into tenant contracts even during years when tax levies remained stable. From this specific detail, it strictly follows that rising taxation was not a necessary prerequisite for tenancy, and therefore other factors could compel these smallholders into tenant contracts.

Adım Adım Çözüm

1
Analyze the core premise regarding smallholders reliant solely on arable plots.
The target sentence specifies that arable-only smallholders 'were forced into tenant contracts even during years of stable tax levies'.
Establishing what happened during periods of stable tax levies isolates whether tax increases were required to force tenancy.
2
Deduce the logical implication of tenancy occurring under stable tax levies.
If smallholders became tenants during years when taxes did not increase, rising taxation cannot be the sole driver, meaning other conditions or factors were sufficient to cause tenancy.
Single-sentence inference on the GMAT requires strict mathematical/logical deduction without introducing unmentioned external concepts.
3
Evaluate the answer choices against this strict deduction.
The choice stating that smallholders lacking pastureland could be forced into tenancy by factors other than tax increases directly matches the logical deduction.
This choice accurately captures the necessary truth without adding extreme qualifiers or unsupported comparative claims.

Anahtar Kavram

Single-Sentence Logical Inference and Strict Deduction
Soru 1213Soru

Consider the following excerpt from a paleoclimatological study:

"While mid-Holocene lacustrine deposits in the Sahara were long thought to reflect widespread, uniform precipitation across North Africa, recent high-resolution isotopic analyses of speleothems in neighboring sub-Mediterranean caves demonstrate that humid episodes during this period were strictly seasonal and spatially compartmentalized."

Based on the excerpt above, evaluate whether the following statement is True or False:

Statement: High-resolution isotopic data from sub-Mediterranean speleothems indicate that humid periods in North Africa during the mid-Holocene were restricted to specific seasons rather than occurring uniformly throughout the year.

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Cevap: True

Cevap

True. The sentence explicitly states that humid episodes were 'strictly seasonal,' which logically implies that precipitation during these periods was concentrated in specific seasons rather than evenly distributed year-round.
The claim accurately reflects the target sentence's explicit finding that mid-Holocene humid episodes were 'strictly seasonal.' In GMAT reading comprehension, 'strictly seasonal' directly supports the deduction that precipitation during these episodes occurred in specific seasons rather than uniformly throughout the year.

Adım Adım Çözüm

1
Identify the key finding reported regarding the temporal distribution of rainfall in the target sentence.
The text states that isotopic analyses of speleothems demonstrate humid episodes were 'strictly seasonal.'
Isolating the explicit finding in the sentence is necessary to verify the deduction.
2
Compare the statement's claim with the textual evidence.
The statement asserts that humid periods were restricted to specific seasons rather than occurring uniformly throughout the year, which directly matches the meaning of 'strictly seasonal.'
A valid GMAT single-sentence inference must be strictly supported by explicit sentence modifiers without extrapolation.

Anahtar Kavram

Single-Sentence Inferences: Deductive reasoning based strictly on explicit modifiers within a single sentence.
Soru 1214Soru

Passage:
In the late twentieth century, several European municipal utility companies introduced feed-in tariffs—guaranteed above-market rates paid to small-scale producers of solar energy—to accelerate renewable energy adoption. Proponents argued that these long-term financial guarantees would insulate domestic solar panel manufacturers from foreign price competition by fostering a reliable local market. In response to these policy incentives, local manufacturing of photovoltaic cells surged dramatically between 1995 and 2002. However, the legislation governing the feed-in tariffs did not specify that equipment must be sourced locally; utilities were required to purchase power from qualified producers regardless of where the producers purchased their solar hardware. Consequently, when Asian manufacturers expanded their production capacity in 2001 and offered solar components at prices substantially lower than European production costs, European solar installation companies increasingly purchased imported hardware to lower their capital expenses while continuing to receive the fixed tariff rates. By 2005, despite record numbers of domestic solar installations, over sixty percent of European solar panel manufacturers faced bankruptcy, and net domestic manufacturing employment in the sector declined.

Statement: European solar installation companies were legally required to use domestically manufactured equipment in order to qualify for fixed feed-in tariff payments.

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Cevap: False

Cevap

The statement is False.
The statement is false because synthesizing two non-contiguous statements in the passage confirms that feed-in tariffs did not require domestic equipment. The text specifies that the legislation did not mandate local sourcing and confirms that installers received fixed tariff rates while utilizing imported hardware.

Adım Adım Çözüm

1
Analyze the passage for legal requirements governing feed-in tariff eligibility.
The passage explicitly notes that the legislation governing feed-in tariffs did not mandate that equipment be sourced locally.
Identifying legislative conditions is essential to determine whether domestic equipment was legally required.
2
Synthesize the legislative rule with the factual outcomes reported later in the passage.
European solar installation companies bought imported Asian hardware and successfully received fixed tariff rates.
Combining the statutory rule with the subsequent behavior of installation companies proves that using imported components did not disqualify firms from tariff payments.

Anahtar Kavram

Multi-Sentence Synthesis Inferences
Soru 1215Soru

Read the passage below and answer the question that follows.

For decades, evolutionary anthropologists seeking to explain the marked expansion of neocortical volume in anthropoid primates predominantly favored the social brain hypothesis. This framework posits that the cognitive demands of navigating complex, dynamic social networks—such as managing tactical deception, coalition formation, and dominance hierarchies—served as the primary selective driver for encephalization. Proponents of this view frequently point to strong correlations between relative neocortex size and mean group size across various extant primate species as empirical confirmation that sociality drove cognitive evolution.

However, recent comparative analyses incorporating broader phylogenetic datasets and ecological variables have challenged the primacy of social driving factors. Researchers examining dietary regimes revealed that frugivorous primates possess significantly larger relative brain sizes than folivorous species of comparable body mass, regardless of group size. Processing patchily distributed, ephemeral fruit resources requires sophisticated spatial memory, temporal mapping, and extractive foraging strategies—cognitive demands that operate independently of social group dynamics. Consequently, while social complexity undoubtedly influenced cognitive architecture, it was likely the metabolic availability of high-energy nutrient sources alongside the spatial-foraging demands of frugivory that established the fundamental evolutionary prerequisite and initial selection pressure for expanded primate brain capacity.

Which of the following best expresses the central thesis of the passage?

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Cevap: While social interaction contributed to primate encephalization, dietary complexity and foraging demands constituted the primary driver and metabolic foundation for brain expansion.

Cevap

The main idea of the passage is that while social complexity played a role in primate brain evolution, dietary factors and spatial foraging demands provided the primary selection pressure and metabolic foundation for encephalization.
The correct answer accurately synthesizes the passage's central thesis. The author begins by summarizing the traditional social brain hypothesis and then uses contrastive structural markers ('However', 'Consequently') to argue that dietary complexity (frugivory) and energy availability were the principal drivers of primate brain expansion, while still acknowledging that social factors played a secondary or complementary role.

Adım Adım Çözüm

1
Analyze the structural organization of the passage.
Paragraph 1 outlines the traditional 'social brain hypothesis'. Paragraph 2 introduces a structural pivot ('However') presenting recent research favoring dietary and ecological drivers.
Identifying paragraph functions clarifies how evidence is structured to support the main argument.
2
Distinguish between the supporting evidence and the author's ultimate conclusion.
The comparison between frugivorous and folivorous primates serves as empirical evidence supporting the broader claim that dietary demands and energy availability drove encephalization.
Specific details must not be mistaken for the comprehensive main thesis.
3
Evaluate the option choices against the identified main thesis.
The option highlighting dietary complexity and foraging demands as the primary driver while acknowledging social contributions accurately captures the entire scope of the passage.
The correct main idea option must encapsulate the author's core claim without overstating or focusing narrowly on sub-details.

Anahtar Kavram

Distinguishing Main Idea from Supporting Evidence
Tahmini Süre:2m 0s
Soru 1216Soru

Biologists have long studied the mutualistic relationship between certain acacia tree species and the Pseudomyrmex ants that inhabit them. The trees provide hollow thorns for shelter and secrete a sugar-rich liquid through structures called extrafloral nectaries to feed the ant colonies. In return, the ants aggressively defend the host plant against herbivorous insects and encroaching vegetation.

To demonstrate that this interaction is an obligate mutualism rather than an incidental association, researcher Janet Miller conducted an exclusion experiment in which ants were chemically removed from a subset of acacia trees. Within weeks, the ant-free trees suffered catastrophic leaf damage from beetles and experienced significantly reduced growth rates compared to the control group. Notably, Miller recorded that ant-free trees produced twice as many extrafloral nectaries during the initial days following ant removal.

While some botanists initially hypothesized that this surge in nectar production represented an evolutionary mechanism to attract replacement ant colonies during crisis events, subsequent physiological analysis revealed a simpler mechanism: nectar secretion is normally suppressed by mechanical vibrations caused by ant patrolling. Thus, the temporary increase in nectar output was merely a physiological byproduct of the ants' physical absence rather than an active, adaptive defense strategy deployed by the tree.

Based on the passage, why does the author mention the "temporary increase in nectar output" in the final paragraph?

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Cevap: To introduce a phenomenon whose initial adaptive explanation is subsequently undermined.

Cevap

The author mentions the temporary increase in nectar output to introduce a phenomenon whose initial adaptive explanation is subsequently undermined by physiological evidence.
The author presents the temporary surge in nectar production to set up a contrast between an early hypothesis (that the tree actively seeks new ant mutualists) and the actual finding (that the lack of ant vibrations simply allows passive nectar flow). Thus, it serves as a phenomenon whose initial adaptive explanation is later shown to be incorrect.

Adım Adım Çözüm

1
Locate the targeted phrase in the passage and identify its context.
The phrase appears in the third paragraph, immediately following the discussion of an initial hypothesis by botanists.
Understanding the immediate structural context reveals how the detail functions in the argument.
2
Analyze how the author uses the detail in relation to surrounding sentences.
The author contrasts the initial adaptive hypothesis (recruiting new ants) with subsequent physiological evidence showing it was just a mechanical byproduct.
Functional role questions test why an author includes a specific detail relative to the paragraph's logical flow.
3
Select the choice that accurately captures this rhetorical function.
The correct choice highlights that the detail introduces a phenomenon whose initial evolutionary explanation was refuted.
This choice directly aligns with the shift from an initial hypothesis to a mechanical explanation.

Anahtar Kavram

Functional Role of Specific Details
Soru 1217Soru

In the mid-nineteenth century, the global expansion of submarine telegraphy encountered a fundamental technological bottleneck: the rapid degradation of undersea cable insulation when exposed to high hydrostatic pressures and saline environments. Early attempts using vulcanized rubber proved disastrous because sulfur cross-links reacted with copper conductors, inducing severe signal attenuation. The breakthrough came when telegraph engineers adopted gutta-percha, a natural latex exudate harvested primarily from trees of the genus Palaquium in Southeast Asia. Unlike rubber, gutta-percha consists predominantly of trans-1,4-polyisoprene, a stereoisomer whose linear molecular configuration enables dense crystalline packing at room temperature. This unique structural attribute confers extraordinary chemical inertness, high dielectric strength, and thermoplastic plasticity, allowing the material to be seamlessly extruded around copper wire. Crucially, when submerged in cold ocean waters, gutta-percha undergoes a phase transformation that increases its density and mechanical rigidity, effectively enhancing its insulating efficacy under deep-sea conditions. However, the rapidly surging demand for submarine cable networks precipitated an ecological crisis in the Malayan archipelago. Harvesters routinely felled mature trees rather than employing sustainable tapping techniques, causing widespread deforestation and threatening local populations of Palaquium gutta. To mitigate these supply disruptions, the British East India Company commissioned botanist Thomas Oxley to investigate cultivation methods. Oxley demonstrated that while cultivated trees required nearly three decades to reach harvesting maturity, systematic bark incisions on standing timber could yield sustainable annual harvests without killing the trees. Despite Oxley’s recommendations, commercial cartels continued destructive harvesting practices until synthetic polyolefins eclipsed natural resins in the mid-twentieth century.

According to the passage, the physical behavior of gutta-percha when exposed to deep ocean submerged conditions is explicitly characterized by which of the following?

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Cevap: A phase transition triggered by cold seawater that increases its density and mechanical stiffness.

Cevap

The physical behavior of gutta-percha underwater is characterized by a phase transition triggered by cold seawater that increases its density and mechanical stiffness.
The correct option directly reflects explicit textual evidence from the middle of the passage, which notes that exposure to cold ocean waters causes gutta-percha to undergo a phase transformation that elevates both its density and mechanical rigidity.

Adım Adım Çözüm

1
Locate the target keywords in the passage corresponding to deep ocean submerged conditions.
Identified the sentence: 'Crucially, when submerged in cold ocean waters, gutta-percha undergoes a phase transformation that increases its density and mechanical rigidity...'
Direct factual retrieval items require matching the specific claim in the text to its exact semantic equivalent in the options.
2
Compare the retrieved textual sentence against the offered choices to find the accurate semantic paraphrase.
The statement describing a 'phase transition triggered by cold seawater that increases its density and mechanical stiffness' precisely captures 'undergoes a phase transformation that increases its density and mechanical rigidity'.
GMAT correct answers paraphrase explicit passage facts using synonymy without altering meaning or scope.

Anahtar Kavram

Direct Factual Retrieval from Academic Reading Passages
Soru 1218Soru

In paleoclimatology, the study of annual tree growth rings—dendroclimatology—provides high-resolution proxy data for historical temperature fluctuations. While tree-ring width primarily reflects annual precipitation and temperature anomalies during the growing season, specialized anatomical features offer even more granular insights into extreme weather events. Among these, "light rings"—tree rings characterized by abnormally thin latewood cell walls—serve as reliable indicators of unseasonal, severe freezing events during the late summer months.

Light rings form when sudden cold spells prematurely halt the lignification process in tracheid cells, the structural elements of wood responsible for water transport. During a typical growing season, trees construct thick-walled latewood cells late in the summer to prepare for dormancy. However, if surface temperatures drop sharply prior to cell wall completion, xylem development ceases prematurely, leaving a distinct band of poorly lignified, pale cells visible under microscopic examination.

Dendroclimatologists have frequently correlated widespread regional occurrences of light rings in high-latitude conifers with sulfur-rich volcanic eruptions. Explosive eruptions inject massive volumes of sulfur dioxide into the stratosphere, forming sulfate aerosols that reflect incoming solar radiation and trigger abrupt global cooling. For instance, tree-ring records from subarctic North America reveal a high frequency of light rings in 536 CE, aligning precisely with atmospheric dust veil records preserved in polar ice cores. Consequently, light ring formation provides a precise chronological marker for identifying major volcanic forcing events in pre-instrumental climate history.

According to the passage, the premature halting of xylem development that produces light rings is directly caused by which of the following?

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Cevap: A sharp drop in surface temperatures occurring before latewood cell wall completion

Cevap

The premature halting of xylem development is caused by a sharp drop in surface temperatures occurring before latewood cell wall completion.
The passage explicitly states in the second paragraph that xylem development ceases prematurely if surface temperatures drop sharply prior to cell wall completion. The correct option accurately paraphrases this factual detail.

Adım Adım Çözüm

1
Identify the target keyword in the question stem
The prompt asks specifically what causes 'xylem development' to cease prematurely during light ring formation.
Direct factual retrieval requires locating the precise sentence addressing the mechanism in the text.
2
Locate explicit passage evidence
Paragraph 2 explicitly states: 'if surface temperatures drop sharply prior to cell wall completion, xylem development ceases prematurely...'
The answer must rely strictly on explicit textual evidence.
3
Match evidence to the correct paraphrased option
The statement directly corresponds to the option referencing a sharp drop in surface temperatures before latewood cell wall completion.
GMAT correct options paraphrase passage facts using semantic equivalents.

Anahtar Kavram

Direct Factual Retrieval
Soru 1219Soru

A citrus orchard harvested two varieties of oranges: Valencia and Navel. The harvest consisted of 800800 crates of Valencia oranges with an average weight of 4545 pounds per crate, and 1,2001,200 crates of Navel oranges with an average weight of 5050 pounds per crate. What is the average weight, in pounds per crate, for the combined harvest of all crates?

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Cevap: 48

Cevap

The average weight of the combined harvest is 48 pounds per crate.
The weighted average is found by calculating the total overall weight divided by the total number of crates. Since Valencia oranges account for 36,000 pounds (800 crates at 45 lbs/crate) and Navel oranges account for 60,000 pounds (1,200 crates at 50 lbs/crate), the total weight is 96,000 pounds across 2,000 crates. Dividing 96,000 by 2,000 gives exactly 48 pounds per crate.

Adım Adım Çözüm

1
Calculate the total weight contributed by each variety of oranges.
Valencia weight = 800×45=36,000800 \times 45 = 36,000 lbs; Navel weight = 1,200×50=60,0001,200 \times 50 = 60,000 lbs.
Total weight equals the product of the number of units and the average weight per unit for each group.
2
Determine the total combined weight and the total number of crates.
Total weight = 36,000+60,000=96,00036,000 + 60,000 = 96,000 lbs; Total crates = 800+1,200=2,000800 + 1,200 = 2,000 crates.
Combined weighted averages require summing total values across all subsets.
3
Divide total weight by total number of crates to find the overall weighted average.
Weighted average = 96,0002,000=48\frac{96,000}{2,000} = 48 lbs per crate.
Weighted mean formula: xˉ=(nixi)ni\bar{x} = \frac{\sum (n_i \cdot x_i)}{\sum n_i}.

Anahtar Kavram

Weighted Average of Combined Sets
Tahmini Süre:1m 30s
Soru 1220Soru

A boutique dairy farm produced 4,0004,000 liters of organic milk in 2021. The annual milk production increased by 15%15\% from 2021 to 2022, decreased by 10%10\% from 2022 to 2023, and then increased by 20%20\% from 2023 to 2024. How many liters of organic milk did the farm produce in 2024?

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Cevap: 4968

Cevap

The farm produced 4,968 liters of organic milk in 2024.
To calculate the final quantity after sequential percent changes, multiply the starting amount by the multiplier for each period. The net expression is 4,000×1.15×0.90×1.204,000 \times 1.15 \times 0.90 \times 1.20. Stepwise, 4,000×1.15=4,6004,000 \times 1.15 = 4,600, then 4,600×0.90=4,1404,600 \times 0.90 = 4,140, and finally 4,140×1.20=4,9684,140 \times 1.20 = 4,968 liters.

Adım Adım Çözüm

1
Calculate milk production in 2022 after a 15% increase.
4,000×1.15=4,6004,000 \times 1.15 = 4,600 liters
An increase of 15% corresponds to multiplying the initial base value by 1+0.15=1.151 + 0.15 = 1.15.
2
Calculate milk production in 2023 after a 10% decrease.
4,600×0.90=4,1404,600 \times 0.90 = 4,140 liters
A decrease of 10% corresponds to multiplying the new base value of 4,600 by 10.10=0.901 - 0.10 = 0.90.
3
Calculate milk production in 2024 after a 20% increase.
4,140×1.20=4,9684,140 \times 1.20 = 4,968 liters
An increase of 20% corresponds to multiplying the current base value of 4,140 by 1+0.20=1.201 + 0.20 = 1.20.

Anahtar Kavram

Successive Percent Change
ÖncekiSayfa 61 / 110Sonraki