Tüm alıştırma soruları

2195 soru

Soru 1041Soru

A security system generates 4-digit passcodes using distinct digits selected from the set {1,2,3,4,5,6,7}\{1, 2, 3, 4, 5, 6, 7\}. How many different 4-digit passcodes can be formed if the first digit must be odd and the last digit must be even?

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Cevap: 240

Cevap

240
To form a valid passcode under the given constraints, we analyze each position step-by-step. The first digit has 4 possible choices (odd numbers: 1, 3, 5, 7), and the fourth digit has 3 possible choices (even numbers: 2, 4, 6). Since the problem specifies that the digits in the passcode must be distinct, choosing the first and last digits consumes 2 of the 7 available digits, leaving 5 digits for the second position and 4 digits for the third position. Applying the Fundamental Counting Principle gives a total of 4×5×4×3=2404 \times 5 \times 4 \times 3 = 240 unique passcodes.

Adım Adım Çözüm

1
Determine choices for the first digit
4 choices
The set contains 4 odd digits: 1, 3, 5, and 7.
2
Determine choices for the fourth (last) digit
3 choices
The set contains 3 even digits: 2, 4, and 6.
3
Determine choices for the second and third digits
5 choices for the second digit, 4 choices for the third digit
All digits in the passcode must be distinct. Having used 2 digits for the first and last positions, 5 digits remain out of 7 for the second slot, and 4 digits remain for the third slot.
4
Apply the Fundamental Counting Principle
4 × 5 × 4 × 3 = 240
Multiply the number of available options for each position to find the total number of distinct passcodes.

Anahtar Kavram

Permutations with Position Restrictions
Soru 1042Soru

For decades, municipal infrastructure policy in emerging market economies operated on the assumption that privatizing municipal water utilities would systematically enhance capital efficiency and service delivery. Proponents argued that private concessionaires, driven by market incentives, could mobilize capital for infrastructure refurbishment far more effectively than capital-constrained public sector providers. However, recent longitudinal analyses of public-private partnerships (PPPs) in Latin America challenge this long-standing paradigm. Researchers observed that while private management frequently achieved short-term gains in billing efficiency and revenue collection, it rarely catalyzed the projected long-term capital investments in underserved peripheral districts. This shortfall stemmed primarily from contractual ambiguities regarding risk allocation, which prompted concessionaires to prioritize immediate cash-flow optimization over high-risk, low-yield infrastructural expansion. Furthermore, regulatory agencies in these jurisdictions often lacked the administrative capacity to enforce universal service mandates, allowing private operators to focus on lucrative commercial sectors while neglecting lower-income residential networks. Consequently, several development economists now advocate for a hybrid governance framework—one that retains municipal oversight of long-term capital assets while contracting out specific operational functions to private entities through performance-tied service agreements. This shift does not represent a complete rejection of market mechanisms, but rather a recalibration that aligns private operational efficiency with public equity goals.

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

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Cevap: To evaluate a traditional model of municipal utility management, analyze the factors leading to its limitations, and present an alternative governance framework.

Cevap

The primary purpose of the passage is to evaluate a traditional model of municipal utility management, analyze the factors leading to its limitations, and present an alternative governance framework.
The correct choice accurately synthesizes the passage's full logical development: introducing the traditional privatization framework, detailing the factors behind its real-world limitations, and concluding with an outline of a hybrid governance alternative proposed by experts.

Adım Adım Çözüm

1
Analyze the structural progression of the passage
The passage begins by outlining a long-held policy paradigm (utility privatization), introduces empirical evidence highlighting its shortfalls, explains the underlying structural causes for those shortfalls, and concludes with a recommended alternative model (hybrid governance).
Tracking the logical development across the text distinguishes the overall rhetorical objective from localized supporting evidence.
2
Differentiate between the core thesis and supporting details
Contractual risk allocation and regulatory enforcement gaps are cited specifically to explain why privatization failed to drive long-term investment, making them supporting points rather than the main focus.
Prevent selecting distractor choices that fixate on isolated explanatory mechanisms.
3
Match the passage's overall scope to the accurate choice
The statement describing an evaluation of a traditional model, an analysis of its limitations, and the presentation of an alternative framework encompasses the complete narrative arc of the passage.
A main idea choice must account for the passage as a whole, including the opening context, the critique, and the final synthesis.

Anahtar Kavram

Identifying Primary Purpose and Structural Organization
Soru 1043Soru

A specialty beverage distributor purchased a crate of rare botanical spirits at a total cost price of $400\$400. The distributor marked up the cost price by 50%50\% to establish the regular list price. During a promotional event, the list price was discounted by x%x\%. If the distributor earned a net profit of 20%20\% on the original cost price of the crate, what is the value of xx?

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Cevap: 2020

Cevap

The value of xx is 2020.
The regular list price is calculated as 1.50×$400=$6001.50 \times \$400 = \$600. Since the distributor earns a 20%20\% profit on the cost price, the discounted selling price must be 1.20×$400=$4801.20 \times \$400 = \$480. The discount amount is $600$480=$120\$600 - \$480 = \$120. Expressed as a percentage of the list price, x=120600×100=20x = \frac{120}{600} \times 100 = 20.

Adım Adım Çözüm

1
Calculate the regular list price based on the 50%50\% markup.
List Price = $400×(1+0.50)=$600\$400 \times (1 + 0.50) = \$600.
Markup is applied directly to the original cost price.
2
Determine the actual selling price after the discount using the 20%20\% net profit target.
Selling Price = $400×(1+0.20)=$480\$400 \times (1 + 0.20) = \$480.
Net profit percentage is calculated relative to the cost price base.
3
Calculate the dollar discount and express it as a percentage of the list price.
Discount Amount = $600$480=$120\$600 - \$480 = \$120. Discount Percentage x%=$120$600×100%=20%x\% = \frac{\$120}{\$600} \times 100\% = 20\%. Thus, x=20x = 20.
Percentage discount is always measured relative to the original list price.

Anahtar Kavram

Markup, Profit, and Successive Percentage Discounts
Soru 1044Soru

Passage:

For decades, classical economic models assumed that expanding the range of choices available to consumers inevitably increases satisfaction by allowing individuals to fine-tune purchases according to their distinct preferences. However, recent empirical studies in behavioral decision theory suggest that an excessive proliferation of options often triggers choice overload, leading to decision fatigue and reduced likelihood of enrollment, particularly in complex financial domains such as employer-sponsored retirement plans. When presented with dozens of investment funds, plan participants frequently default to non-participation or select suboptimal default options rather than conducting a comprehensive evaluation of available assets. In response to these findings, some behavioral economists advocate for a strategy known as 'choice architecture,' which simplifies the decision environment by curating a streamlined subset of core options alongside well-calibrated default settings. Nonetheless, critics of choice architecture argue that restricting choice menus risks paternalistic bias, potentially steering investors away from specialized funds that could better serve their long-term financial goals. Thus, while curated choice menus demonstrably mitigate the paralyzing effects of choice overload, structural design decisions in financial products must carefully balance cognitive ease with individual investor autonomy.

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

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Cevap: Examine the tension between choice overload and curated option menus, emphasizing the balance required between decision efficiency and consumer autonomy.

Cevap

The primary purpose of the passage is to examine the tension between choice overload and curated option menus, emphasizing the balance required between decision efficiency and consumer autonomy.
The correct answer accurately captures the main thrust of the passage. The text introduces classical assumptions, presents empirical evidence of choice overload, outlines choice architecture as a counter-strategy, acknowledges objections regarding paternalism, and concludes that product designs must balance cognitive ease with investor autonomy.

Adım Adım Çözüm

1
Analyze the structural development of the passage.
The passage begins by outlining classical assumptions, introduces counter-evidence regarding choice overload, presents 'choice architecture' as a remedy, presents counter-arguments concerning paternalism, and concludes with a synthesizing statement.
Tracking structural transitions reveals the overarching purpose beyond supporting details.
2
Identify the author's final conclusion and main thesis.
The author concludes that financial product design must carefully balance cognitive ease (mitigating choice overload) with individual investor autonomy.
The concluding sentence provides the main takeaway that ties together the competing viewpoints.
3
Evaluate the answer choices against the overall passage scope.
The option advocating a balance between decision efficiency and consumer autonomy correctly reflects the overall trajectory and main thesis of the passage.
Eliminate choices that focus on minor details, overstate author tone, or introduce out-of-scope claims.

Anahtar Kavram

Identifying Primary Purpose in Reading Comprehension
Tahmini Süre:1m 30s
Soru 1045Soru

For decades, economic historians analyzing the rapid adoption of synthetic nitrogen fertilizers in early twentieth-century European agriculture relied on a technological-deterministic model, which posited that yield gains alone dictated the farm-level transition from traditional crop rotations to chemical inputs. Proponents argued that the undeniable energetic efficiency of synthetic nitrogen rendered traditional soil replenishment methods—such as legume fallowing—obsolete. However, this explanatory framework was later challenged by social constructivists, who demonstrated that state subsidies, chemical cartel pricing strategies, and national security directives during wartime supply disruptions were the primary drivers accelerating adoption, independent of immediate agronomic yield differentials.

Recently, revisionist scholars have argued that both perspectives oversimplify the transition by treating agricultural communities as passive recipients of macro-level forces. Drawing on micro-historical records of regional peasant cooperatives, these scholars reveal that adoption rates varied significantly even between adjacent districts sharing identical ecological constraints and institutional pricing. They contend that local informal credit networks and traditional land-tenure customs either catalyzed or severely hindered chemical fertilizer integration. By demonstrating that adoption was neither an inevitable technological triumph nor a top-down institutional imposition, but rather a contingent process mediated by localized social practices, the revisionists present a far more comprehensive paradigm of technological diffusion.

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

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Cevap: Evaluate two established explanations for a historical technological transition and present a nuanced alternative supported by localized evidence.

Cevap

The primary purpose of the passage is to evaluate two established explanations for a historical technological transition and present a nuanced alternative supported by localized evidence.
The passage begins by outlining two traditional perspectives (technological determinism and social constructivism) regarding synthetic fertilizer adoption, and then shifts to highlight recent revisionist research that uses micro-historical data on local credit and land-tenure customs to offer a more nuanced, integrated framework. The option stating that the passage evaluates two established explanations and introduces a nuanced alternative accurately synthesizes this two-part structure.

Adım Adım Çözüm

1
Analyze the structural movement of the passage across paragraphs.
Paragraph 1 introduces technological determinism and its counter-perspective, social constructivism. Paragraph 2 introduces revisionist scholarship that critiques both established models for ignoring micro-level factors.
Tracking structural transitions reveals the author's overall trajectory and objective.
2
Identify the primary thesis and author stance.
The author focuses on how revisionist scholars present a 'far more comprehensive paradigm' by showing that both traditional macro-models fail to account for local variation.
The main idea must encompass both the critique of older views and the introduction of the new perspective.
3
Evaluate option candidates against the identified passage purpose.
The option describing the evaluation of two established views alongside a nuanced alternative grounded in localized evidence matches the overall passage scope perfectly.
Distractors either focus on minor supporting details, distort the author's stance, or use overly extreme claims.

Anahtar Kavram

Identifying Primary Purpose in Multi-Viewpoint Passages
Tahmini Süre:2m 30s
Soru 1046Soru

If K=2a×3b×5cK = 2^a \times 3^b \times 5^c, where aa, bb, and cc are positive integers, such that 15K15K has 15 more positive factors than KK, and 6K6K has 12 more positive factors than KK, what is the total number of positive factors of KK?

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Cevap: 12

Cevap

The total number of positive factors of KK is 12.
By setting up factor count equations from prime exponents, we find a=2,b=1,c=1a=2, b=1, c=1. Applying the formula (a+1)(b+1)(c+1)(a+1)(b+1)(c+1) yields (3)(2)(2)=12(3)(2)(2) = 12.

Adım Adım Çözüm

1
Set up the formula for the number of positive factors of KK, 15K15K, and 6K6K.
For K=2a3b5cK = 2^a \cdot 3^b \cdot 5^c, the number of factors is d(K)=(a+1)(b+1)(c+1)d(K) = (a+1)(b+1)(c+1). For 15K=2a3b+15c+115K = 2^a \cdot 3^{b+1} \cdot 5^{c+1}, d(15K)=(a+1)(b+2)(c+2)d(15K) = (a+1)(b+2)(c+2). For 6K=2a+13b+15c6K = 2^{a+1} \cdot 3^{b+1} \cdot 5^c, d(6K)=(a+2)(b+2)(c+1)d(6K) = (a+2)(b+2)(c+1).
Prime factorizations determine the number of positive factors via the product of (exponent + 1).
2
Express the given factor differences algebraically.
d(15K)d(K)=(a+1)[(b+2)(c+2)(b+1)(c+1)]=(a+1)(b+c+3)=15d(15K) - d(K) = (a+1)[(b+2)(c+2) - (b+1)(c+1)] = (a+1)(b+c+3) = 15. Also, d(6K)d(K)=(c+1)[(a+2)(b+2)(a+1)(b+1)]=(c+1)(a+b+3)=12d(6K) - d(K) = (c+1)[(a+2)(b+2) - (a+1)(b+1)] = (c+1)(a+b+3) = 12.
Factor out common terms to simplify the system of equations.
3
Solve for the positive integers aa, bb, and cc.
Since b1b \ge 1 and c1c \ge 1, b+c+35b+c+3 \ge 5. The only factor of 15 greater than or equal to 5 is 5 (since b+c+3=15b+c+3=15 would require a=0a=0). Thus b+c+3=5    b=1,c=1b+c+3=5 \implies b=1, c=1 and a+1=3    a=2a+1=3 \implies a=2. Checking in the second equation: (1+1)(2+1+3)=26=12(1+1)(2+1+3) = 2 \cdot 6 = 12, which holds.
Integer constraints limit the potential factor pairs of 15.
4
Calculate d(K)d(K).
d(K)=(2+1)(1+1)(1+1)=322=12d(K) = (2+1)(1+1)(1+1) = 3 \cdot 2 \cdot 2 = 12.
Substitute a=2,b=1,c=1a=2, b=1, c=1 into the factor counting formula.

Anahtar Kavram

Prime Factorization and Number of Divisors
Tahmini Süre:2m 0s
Soru 1047Soru

Read the following passage:

For decades, archaeologists attributed the apparent mid-eighth millennium BCE abandonment of mega-sites—large nucleated agricultural settlements—in the southern Levant primarily to sudden regional climatic aridification. Under this conventional paradigm, deteriorating environmental conditions rendered intensive rain-fed cultivation unviable, forcing sedentary communities to disperse or revert to nomadic pastoralism. However, recent high-resolution zooarchaeological analysis of faunal remains and phytolith evidence from peripheral sites suggests a more nuanced structural transition rather than a catastrophic demographic collapse.

Researchers now note that while central mega-sites were indeed vacated, regional biomass indicators and total regional population estimates remained remarkably stable across the transition period. Rather than succumbing to climate-induced resource scarcity, late Neolithic societies appear to have deliberately decentralized their settlement patterns in response to localized environmental degradation caused by excessive fuelwood harvesting and soil salinization. By redistributing populations into smaller, ecologically dispersed hamlets and adopting integrated agro-pastoral strategies, these communities effectively mitigated anthropogenic ecological stress. Thus, the shift away from mega-sites represents an adaptive strategy of spatial reorganization and subsistence diversification, challenging long-held assumptions that prehistoric site abandonment necessarily denotes societal collapse.

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

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Cevap: Reevaluate a long-standing archaeological consensus regarding prehistoric site abandonment by presenting recent empirical evidence of adaptive settlement reorganization.

Cevap

The primary purpose of the passage is to reevaluate a long-standing archaeological consensus regarding prehistoric site abandonment by presenting recent empirical evidence of adaptive settlement reorganization.
The passage opens by establishing a traditional consensus (that climate change caused mega-site abandonment and collapse), transitions to new evidence showing population stability and human adaptation, and concludes that the abandonment represents spatial reorganization rather than societal collapse. The option stating that the purpose is to reevaluate a long-standing archaeological consensus by presenting evidence of adaptive reorganization perfectly matches this primary focus.

Adım Adım Çözüm

1
Analyze the structural organization of the passage
Paragraph 1 presents the traditional view (site abandonment was caused by climate-induced collapse) and introduces a contrastive pivot ('However...') asserting that recent evidence points to structural transition rather than collapse.
Identifying transition markers clarifies the author's main thesis.
2
Evaluate the supporting evidence and authorial conclusion
Paragraph 2 details evidence of stable population estimates, localized environmental degradation, and deliberate decentralization into hamlets, concluding with the explicit main idea: site shift was an adaptive strategy challenging traditional collapse assumptions.
Synthesizing the conclusion ensures the primary purpose covers the full passage scope.
3
Select the choice that reflects overall scope without overstating or narrowing
The statement emphasizing reevaluating an archaeological consensus through evidence of adaptive reorganization accurately captures the overarching purpose.
The correct primary purpose choice must encompass both the critique of the old view and the introduction of the new perspective.

Anahtar Kavram

Primary Purpose and Main Idea in Reading Comprehension
Soru 1048Soru

Read the following excerpt from an archival musicology study:

"While nineteenth-century catalogers attributed the structural shifts in late-seventeenth-century Venetian polyphonic manuscripts primarily to individual stylistic evolution, recent codicological analysis reveals that the abrupt transition from heavy rag-paper to thin import sheets—attributable to severe textile supply disruptions following the 1686 Ottoman trade embargo—forced copyists to eliminate dense marginal annotations, thereby compelling composers to incorporate performance instructions directly into the primary musical stave."

Statement: Based on the passage, the removal of dense marginal annotations in late-seventeenth-century Venetian polyphonic manuscripts was an indirect consequence of geopolitical events that disrupted the availability of textiles.

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Cevap: True

Cevap

True. The sentence explicitly links the elimination of marginal annotations to the adoption of thin import sheets, which was caused by textile disruptions stemming directly from the 1686 Ottoman trade embargo.
The correct evaluation is True. The single sentence constructs a multi-stage causal sequence: the 1686 Ottoman trade embargo (a geopolitical event) caused textile supply disruptions, which necessitated using thin import paper, which forced copyists to remove marginal annotations. Thus, the removal of annotations was an indirect consequence of geopolitical events affecting textile supplies.

Adım Adım Çözüm

1
Analyze the structural role of the parenthetical clause within the single target sentence.
Identified that the transition to 'thin import sheets' is directly attributed to 'severe textile supply disruptions following the 1686 Ottoman trade embargo'.
Tracing causal modifiers within complex single sentences is necessary to establish logically valid inferences on the GMAT.
2
Connect the paper transition to its downstream structural consequence.
The use of thin import sheets 'forced copyists to eliminate dense marginal annotations'.
This establishes the second link in the causal chain.
3
Synthesize the multi-link causal chain from the geopolitical event to the annotation removal.
Ottoman trade embargo (geopolitical event) → textile supply disruptions → transition to thin import sheets → removal of marginal annotations.
Synthesizing these links demonstrates that the removal of marginal annotations was indeed an indirect consequence of geopolitical events affecting textile availability.

Anahtar Kavram

Single-Sentence Inferences: Tracking Causal Chains and Parenthetical Modifiers
Soru 1049Soru

Let mm and nn be integers such that 4m6-4 \le m \le 6 and 8n3-8 \le n \le 3. If m2n<0m^2 n < 0 and m+n>0m + n > 0, what is the minimum possible value of the product mnm \cdot n?

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Cevap: -30

Cevap

The minimum possible value of mnm \cdot n is 30-30.
The correct answer is -30. Analyzing m2n<0m^2 n < 0 shows that nn must be negative and mm cannot be zero. The condition m+n>0m + n > 0 implies m>n=nm > -n = |n|, making mm positive. Since m6m \le 6, the maximum possible value for n|n| is 5, which corresponds to n=5n = -5. When n=5n = -5, mm must be strictly greater than 5, leaving m=6m = 6 as the only valid value. The product is 6×(5)=306 \times (-5) = -30, which is the minimum value achievable under all constraints.

Adım Adım Çözüm

1
Determine the signs of mm and nn using the given inequalities.
n<0n < 0 and m>0m > 0 with m0m \ne 0.
Since m2m^2 is strictly positive for any non-zero integer mm, m2n<0m^2 n < 0 forces n<0n < 0. Then m+n>0m + n > 0 requires m>n>0m > -n > 0.
2
Find the range of valid integer values for nn.
n{5,4,3,2,1}n \in \{-5, -4, -3, -2, -1\}.
Since m6m \le 6 and m>nm > -n, we must have n5-n \le 5, which gives n5n \ge -5.
3
Evaluate the minimum product mnm \cdot n across all allowed values of nn.
The minimum product is 30-30, occurring when n=5n = -5 and m=6m = 6.
To minimize a negative product, maximize the absolute product mnm \cdot |n|. When n=5n = -5, mm must be 66, yielding 6(5)=306 \cdot (-5) = -30.

Anahtar Kavram

Positive and Negative Number Properties with Inequalities
Soru 1050Soru

A quality control inspector evaluates components from two separate production lines. Line 1 produces a batch of 1212 components containing 44 defective and 88 non-defective components. Line 2 produces a batch of 1010 components containing 22 defective and 88 non-defective components. The inspector randomly selects 22 components from Line 1's batch without replacement, and then randomly selects 11 component from Line 2's batch. What is the probability that exactly two of the three selected components are defective?

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Cevap: 28165\frac{28}{165}

Cevap

The probability that exactly two of the three selected components are defective is 28165\frac{28}{165}.
To find the probability of selecting exactly two defective components across both production lines, we sum the probabilities of two mutually exclusive events: (1) selecting two defective components from Line 1 (without replacement) and one non-defective component from Line 2, which has probability 412×311×810=12165\frac{4}{12} \times \frac{3}{11} \times \frac{8}{10} = \frac{12}{165}; and (2) selecting one defective and one non-defective component from Line 1 and one defective component from Line 2, which has probability 2×412×811×210=161652 \times \frac{4}{12} \times \frac{8}{11} \times \frac{2}{10} = \frac{16}{165}. Adding these gives 12165+16165=28165\frac{12}{165} + \frac{16}{165} = \frac{28}{165}.

Adım Adım Çözüm

1
Identify the mutually exclusive cases that yield exactly two defective components.
Case 1: Draw 2 defective components from Line 1 AND 1 non-defective component from Line 2.
Case 2: Draw 1 defective and 1 non-defective component from Line 1 AND 1 defective component from Line 2.
The overall target outcome can be satisfied in two distinct ways depending on which line provides the defective components.
2
Calculate the probability for Case 1.
P(Case 1)=(412×311)×810=111×45=455=12165P(\text{Case 1}) = \left(\frac{4}{12} \times \frac{3}{11}\right) \times \frac{8}{10} = \frac{1}{11} \times \frac{4}{5} = \frac{4}{55} = \frac{12}{165}.
Drawing without replacement from Line 1 gives a probability of 412×311=111\frac{4}{12} \times \frac{3}{11} = \frac{1}{11}. Multiplying by the probability of picking a non-defective component from Line 2 (810\frac{8}{10}) yields 455\frac{4}{55}.
3
Calculate the probability for Case 2.
P(Case 2)=(2×412×811)×210=1633×15=16165P(\text{Case 2}) = \left(2 \times \frac{4}{12} \times \frac{8}{11}\right) \times \frac{2}{10} = \frac{16}{33} \times \frac{1}{5} = \frac{16}{165}.
The probability of getting 1 defective and 1 non-defective component from Line 1 in 2 draws without replacement is 2×412×811=16332 \times \frac{4}{12} \times \frac{8}{11} = \frac{16}{33}. Multiplying by the probability of picking a defective component from Line 2 (210\frac{2}{10}) yields 16165\frac{16}{165}.
4
Sum the probabilities of Case 1 and Case 2.
P(Total)=12165+16165=28165P(\text{Total}) = \frac{12}{165} + \frac{16}{165} = \frac{28}{165}.
Since the two cases are mutually exclusive, their individual probabilities are added.

Anahtar Kavram

Probability of Independent and Dependent Events
Tahmini Süre:2m 0s
Soru 1051Soru

A jewelry store window displays 66 distinct luxury watches—33 gold watches and 33 silver watches—in a single straight line from left to right. If no two gold watches can be placed adjacent to each other, how many different linear arrangements of the 66 watches are possible?

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Cevap: 144

Cevap

144
To place items such that no two gold watches are adjacent, we use the gap method. First, arrange the 3 distinct silver watches, which can be done in 3!=63! = 6 ways. Placing these 3 silver watches creates 4 potential spaces (one at each end and two between the silver watches). Next, select 3 of these 4 spaces to place the gold watches, which can be done in (43)=4\binom{4}{3} = 4 ways. Finally, arrange the 3 distinct gold watches within the selected spaces in 3!=63! = 6 ways. Multiplying these possibilities gives 6×4×6=1446 \times 4 \times 6 = 144 total distinct arrangements.

Adım Adım Çözüm

1
Calculate the arrangements of the 3 distinct silver watches.
3! = 6 ways
The 3 silver watches are distinct and can be arranged among themselves in 3! ways.
2
Determine the available positions (gaps) for the gold watches.
4 available gaps
Placing 3 silver watches in a line creates 4 potential spaces (before the first, between adjacent pairs, and after the last) to ensure non-adjacency.
3
Select positions and arrange the 3 distinct gold watches.
C(4, 3) × 3! = 4 × 6 = 24 ways
Choosing 3 out of 4 gaps gives C(4, 3) = 4 combinations, and ordering the 3 distinct gold watches in those selected gaps gives 3! = 6 arrangements.
4
Multiply the possibilities from all independent steps using the Fundamental Counting Principle.
6 × 24 = 144
The total number of valid linear arrangements is the product of the number of ways to complete each step.

Anahtar Kavram

Linear Permutations with Non-Adjacent Restrictions (Gap Method)
Tahmini Süre:2m 0s
Soru 1052Soru

If 8x4x116x+1=32\frac{8^x \cdot 4^{x-1}}{16^{x+1}} = 32, what is the value of xx?

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Cevap: 11

Cevap

The value of xx is 11.
Rewriting all bases as powers of 2 yields 23x22x224x+4=25\frac{2^{3x} \cdot 2^{2x-2}}{2^{4x+4}} = 2^5. Simplifying the left side gives 2x6=252^{x-6} = 2^5. Equating exponents results in x6=5x - 6 = 5, giving x=11x = 11.

Adım Adım Çözüm

1
Express all bases as powers of 2.
8=238 = 2^3, 4=224 = 2^2, 16=2416 = 2^4, and 32=2532 = 2^5.
Converting to a common base allows exponents to be combined using standard exponent laws.
2
Simplify the numerator and denominator using the power rule (am)n=amn(a^m)^n = a^{mn} and product rule aman=am+na^m \cdot a^n = a^{m+n}.
Numerator: 23x22x2=25x22^{3x} \cdot 2^{2x-2} = 2^{5x-2}. Denominator: 24(x+1)=24x+42^{4(x+1)} = 2^{4x+4}.
Distribute exponents carefully when multiplying powers with equal bases.
3
Apply the quotient rule aman=amn\frac{a^m}{a^n} = a^{m-n} to combine the left side into a single power of 2.
25x224x+4=2(5x2)(4x+4)=2x6\frac{2^{5x-2}}{2^{4x+4}} = 2^{(5x-2) - (4x+4)} = 2^{x-6}.
Subtract the denominator's exponent from the numerator's exponent.
4
Equate exponents and solve for xx.
2x6=25    x6=5    x=112^{x-6} = 2^5 \implies x - 6 = 5 \implies x = 11.
Since the bases are identical (22), the exponent expressions must be equal.

Anahtar Kavram

Solving exponential equations by expressing all numbers with a common base and applying exponent rules.
Soru 1053Soru

A corporate board of 7 members—consisting of 4 senior executives (including the CEO and the COO) and 3 junior associates—is to be seated in a single row of 7 chairs for a press conference. If the 3 junior associates must sit in adjacent chairs, and the CEO and the COO cannot sit next to each other, in how many different linear arrangements can the 7 members be seated?

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Cevap: 432

Cevap

432
To satisfy the condition that the 3 junior associates sit together, we treat them as 1 block with 3!=63! = 6 internal orderings. Combining this block with the 4 senior executives yields 5 entities, which can be arranged in 5!=1205! = 120 ways, giving 120×6=720120 \times 6 = 720 total arrangements with the juniors seated together. To enforce that the CEO and COO cannot sit together, we subtract the arrangements where they do sit together: treating the CEO and COO as a block gives 4 entities to arrange (4!=244! = 24), with 2!=22! = 2 ways to arrange CEO and COO, and 3!=63! = 6 ways for the junior block, totaling 24×2×6=28824 \times 2 \times 6 = 288 restricted cases. Subtracting 288 from 720 gives 432 valid arrangements.

Adım Adım Çözüm

1
Group the 3 junior associates into a single block.
The 3 junior associates can be arranged internally within their block in 3!=63! = 6 ways. Treating this block as 1 single element along with the 4 senior executives gives a total of 5 items to arrange.
The condition specifies that all 3 junior associates must sit in adjacent chairs.
2
Calculate total arrangements where junior associates sit together without CEO/COO restrictions.
The 5 items (1 block + 4 senior executives) can be arranged in 5!=1205! = 120 ways. Including internal block arrangements gives 120×6=720120 \times 6 = 720 ways.
Applying the Fundamental Counting Principle to the 5 units and the 3 internal positions.
3
Calculate unwanted arrangements where the CEO and COO sit next to each other (with junior associates together).
Group the CEO and COO into a second block with 2!=22! = 2 internal arrangements. Now there are 4 items to arrange (Junior block, CEO-COO block, and 2 other senior executives). Total unwanted arrangements: 4!×3!×2!=24×6×2=2884! \times 3! \times 2! = 24 \times 6 \times 2 = 288 ways.
To find valid non-adjacent arrangements, subtract adjacent CEO-COO arrangements from total junior-grouped arrangements.
4
Subtract the unwanted arrangements from the total grouped arrangements.
720288=432720 - 288 = 432 valid seating arrangements.
Complementary counting provides a direct solution.

Anahtar Kavram

Linear Permutations with Grouping and Complementary Non-Adjacency Constraints
Soru 1054Soru

A municipal study in Westlake indicates that installing high-intensity LED streetlights along commercial corridors reduced nighttime pedestrian accidents by 30 percent over a twelve-month period. Consequently, city council members plan to install identical LED lighting across all residential neighborhoods in Westlake to achieve a similar reduction in accidents. Which of the following statements functions as the primary premise supporting the city council members' plan?

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Cevap: Installing high-intensity LED streetlights along commercial corridors was followed by a 30 percent drop in nighttime pedestrian accidents over twelve months.

Cevap

The statement citing the 30 percent reduction in nighttime pedestrian accidents following the installation of high-intensity LED streetlights along commercial corridors serves as the primary supporting premise.
The correct answer correctly identifies the concrete factual finding of the municipal study—specifically, the 30 percent decrease in nighttime pedestrian accidents along commercial corridors after LED installation. In Critical Reasoning structure, this empirical finding serves as the primary premise supporting the council's conclusion to extend the project to residential areas.

Adım Adım Çözüm

1
Identify the main conclusion of the argument.
The main conclusion is the city council's plan to install identical LED lighting across residential neighborhoods to reduce accidents.
Determining the conclusion helps distinguish what claim is being defended from the evidence used to defend it.
2
Locate the explicit evidence or data offered in support of this conclusion.
The factual finding from the Westlake study showing a 30 percent reduction in accidents over twelve months provides the empirical basis for the plan.
Premises are explicit statements of fact or evidence offered to justify the conclusion.

Anahtar Kavram

Identifying Premises and Evidence
Soru 1055Soru

A panel discussion features 6 participants: 3 scientists, 2 economists, and 1 moderator. In how many different linear seating arrangements can these 6 participants be seated in a single row of 6 chairs if all 3 scientists must sit in adjacent seats?

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Cevap: 144144

Cevap

The total number of valid seating arrangements is 144.
To arrange participants under the condition that all 3 scientists sit together, treat the 3 scientists as a single block. This leaves 4 units to arrange: 1 block of scientists, 2 economists, and 1 moderator. These 4 units can be arranged in a row in 4!=244! = 24 ways. Furthermore, within the scientist block, the 3 individual scientists can be arranged in 3!=63! = 6 distinct orders. By the fundamental counting principle, multiplying the arrangements of the main units by the internal arrangements of the block gives 24×6=14424 \times 6 = 144 total valid seating arrangements.

Adım Adım Çözüm

1
Group the restricted items into a single block.
Treat the 3 scientists as 1 single block unit.
Because the 3 scientists must sit together in adjacent seats, they move as a single block along with the other participants.
2
Calculate the number of arrangements for the distinct units.
There are 4 units to arrange (1 scientist block + 2 economists + 1 moderator), giving 4!=244! = 24 arrangements.
The Fundamental Counting Principle states that nn distinct items can be linearly arranged in n!n! ways.
3
Calculate the internal arrangements within the block.
The 3 scientists can be arranged among themselves within their block in 3!=63! = 6 ways.
The order of the individual scientists inside the block matters.
4
Multiply the unit arrangements by the internal arrangements.
Total arrangements = 4!×3!=24×6=1444! \times 3! = 24 \times 6 = 144.
By the multiplication principle, the total ways to complete both independent arrangement tasks is the product of their individual possibilities.

Anahtar Kavram

Permutations with Adjacency Restrictions (Block Method)
Tahmini Süre:1m 30s
Soru 1056Soru

If xx and yy are non-zero real numbers such that xyx>2\frac{x - y}{x} > 2 and xy2<0x y^2 < 0, which of the following inequalities must be true?

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Cevap: x+y>0x + y > 0

Cevap

x+y>0x + y > 0
From xy2<0x y^2 < 0, since y0y \neq 0, y2y^2 is strictly positive, which forces x<0x < 0. Next, expanding xyx>2\frac{x - y}{x} > 2 by multiplying both sides by negative xx reverses the inequality direction to xy<2xx - y < 2x. Subtracting xx from both sides gives y<x-y < x, which is equivalent to x+y>0x + y > 0. Thus, x+y>0x + y > 0 must always be true.

Adım Adım Çözüm

1
Determine the sign of xx using xy2<0x y^2 < 0.
Since y0y \neq 0, y2>0y^2 > 0. For the product xy2x y^2 to be negative, xx must be negative (x<0x < 0).
A positive quantity multiplied by a negative quantity yields a negative product.
2
Simplify the inequality xyx>2\frac{x - y}{x} > 2 taking the sign of xx into account.
Multiplying both sides by xx (and reversing the inequality because x<0x < 0) gives xy<2xx - y < 2x.
Multiplying or dividing an inequality by a negative value reverses the inequality sign.
3
Rearrange the terms of xy<2xx - y < 2x to isolate the relationship between xx and yy.
Subtracting xx from both sides yields y<x-y < x, which rearranges to x+y>0x + y > 0 (or y>xy > -x).
Adding yy to both sides converts y<x-y < x directly into x+y>0x + y > 0.

Anahtar Kavram

Deducing signs and algebraic bounds in inequalities involving negative variables
Tahmini Süre:1m 30s
Soru 1057Soru

A jogger runs from point A to point B at a constant speed of 88 miles per hour and then immediately returns from point B to point A along the exact same route at a constant speed of 1212 miles per hour. If the total time for the entire round trip is 55 hours, what is the distance, in miles, from point A to point B?

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Cevap: 24

Cevap

The distance from point A to point B is 24 miles.
Let dd be the distance in miles between point A and point B. The time taken for the outbound journey is d8\frac{d}{8} hours, and the time taken for the return journey is d12\frac{d}{12} hours. Since the total time for the round trip is 55 hours, we set up the equation d8+d12=5\frac{d}{8} + \frac{d}{12} = 5. Finding a common denominator of 2424, the equation becomes 3d+2d24=5\frac{3d + 2d}{24} = 5, which simplifies to 5d24=5\frac{5d}{24} = 5. Multiplying both sides by 2424 gives 5d=1205d = 120, and dividing by 55 yields d=24d = 24 miles.

Adım Adım Çözüm

1
Define the variable dd as the distance in miles between point A and point B, and express the time for each leg of the trip.
Outbound time = d8\frac{d}{8} hours, Return time = d12\frac{d}{12} hours.
Using the fundamental rate formula t=drt = \frac{d}{r}, time equals distance divided by speed.
2
Sum the time spent on the outbound leg and the return leg to match the total round-trip time.
d8+d12=5\frac{d}{8} + \frac{d}{12} = 5.
The total time for the trip is given as 55 hours.
3
Find a common denominator to add the algebraic fractions and solve for dd.
3d+2d24=5    5d24=5    5d=120    d=24\frac{3d + 2d}{24} = 5 \implies \frac{5d}{24} = 5 \implies 5d = 120 \implies d = 24.
The common denominator of 88 and 1212 is 2424. Simplifying the resulting linear equation yields the one-way distance.

Anahtar Kavram

Rate, Time, and Distance Problems: d=rtd = r \cdot t. Total trip time is the sum of individual leg times (ttotal=t1+t2t_{\text{total}} = t_1 + t_2).
Tahmini Süre:1m 30s
Soru 1058Soru

Passage:

For decades, paleoceanographers attributed the pronounced decrease in atmospheric carbon dioxide during glacial maxima primarily to enhanced iron fertilization of the Southern Ocean. According to this traditional framework, wind-borne dust delivered abundant iron to high-nutrient, low-chlorophyll marine zones, dramatically stimulating phytoplankton growth and drawing atmospheric carbon down into the deep ocean. However, recent sediment core analyses from sub-Antarctic basins reveal a critical structural limitation in this single-nutrient mechanism. While iron influx indeed stimulated transient diatom blooms, long-term carbon sequestration was fundamentally constrained by the concurrent exhaustion of dissolved silicic acid, which is essential for diatom frustule synthesis. When silicic acid levels plummeted, non-silicified phytoplankton species replaced diatoms; these alternative taxa were far less efficient at exporting organic carbon past the thermocline due to their lower sinking velocity and higher remineralization rates in shallow waters. Consequently, rather than validating the iron-fertilization model as a sufficient standalone explanation for glacial carbon drawdown, these empirical findings demonstrate that sustained oceanic carbon storage depended on a delicate biogeochemical synergy between micronutrient supply and lower-latitude nutrient upwelling. Ultimately, the researchers contend that climate models isolating iron dust deposition as the sole driver of glacial-interglacial atmospheric fluctuations significantly overstate its efficacy while overlooking the structural dependencies of marine food webs.

Based on the passage above, determine whether the following statement correctly identifies the primary purpose of the passage:

The primary purpose of the passage is to argue that iron fertilization was entirely ineffective in increasing biological productivity during glacial maxima.

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Cevap: False

Cevap

False. The statement incorrectly characterizes the primary purpose of the passage by asserting an extreme claim that contradicts the author's nuanced argument.
The statement is false because the author explicitly acknowledges that iron influx stimulated transient diatom blooms, confirming an increase in biological productivity. The passage's primary purpose is to reevaluate the scope of the iron fertilization hypothesis by showing that iron alone cannot account for long-term carbon sequestration without considering silicic acid dynamics.

Adım Adım Çözüm

1
Analyze the passage's logical organization and structural pivots.
The passage presents a traditional theory (iron fertilization causes glacial carbon drawdown), introduces a limitation via a pivot ('However'), presents empirical findings (silicic acid exhaustion), and concludes that climate models relying solely on iron dust overstate its efficacy.
Understanding the overall rhetorical flow is essential to pinpointing the author's primary objective.
2
Evaluate the specific assertion in the statement against the text.
The statement claims the passage aims to prove iron fertilization was 'entirely ineffective' at increasing biological productivity.
Determining truth value requires testing whether the scope and tone of the statement match the passage.
3
Identify textual evidence addressing biological productivity.
The passage explicitly states that 'iron influx indeed stimulated transient diatom blooms,' which confirms biological productivity did increase.
Because the author concedes a partial productivity increase while critiquing the model's standalone sufficiency for carbon export, the statement distorts the passage's primary intent.

Anahtar Kavram

Distinguishing Primary Purpose from Overstated or Extreme Distractions
Soru 1059Soru

A container holds 66 red tokens and nn blue tokens, where nn is a positive integer. Two tokens are drawn at random from the container one after another without replacement. If the probability that the first token drawn is red and the second token drawn is blue is equal to 935\frac{9}{35}, what is the value of nn?

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Cevap: 9

Cevap

The value of nn is 99.
By applying the multiplication rule for dependent events without replacement, the probability is 66+n×n5+n=935\frac{6}{6+n} \times \frac{n}{5+n} = \frac{9}{35}. Simplifying and solving the resulting quadratic equation 3n237n+90=03n^2 - 37n + 90 = 0 yields n=9n = 9 as the only integer solution.

Adım Adım Çözüm

1
Formulate the joint probability for dependent events.
The probability of drawing a red token first then a blue token second is 66+n×n5+n\frac{6}{6+n} \times \frac{n}{5+n}.
Because sampling is done without replacement, the total number of remaining tokens decreases from 6+n6+n to 5+n5+n for the second draw.
2
Set up the algebraic equation with the given probability.
6n(6+n)(5+n)=935\frac{6n}{(6+n)(5+n)} = \frac{9}{35}
Equate the theoretical probability expression to the given value 935\frac{9}{35}.
3
Simplify and expand the equation.
Divide both sides of the numerator by 33: \frac{2n}{n^2 + 11n + 30} = \frac{3}{35}. Cross-multiplying yields 70n=3n2+33n+9070n = 3n^2 + 33n + 90.
Simplifying ratios makes polynomial expansion easier.
4
Solve the quadratic equation for nn.
Rearrange to 3n237n+90=03n^2 - 37n + 90 = 0, which factors into (3n10)(n9)=0(3n - 10)(n - 9) = 0.
Find the roots of the quadratic equation.
5
Select the valid integer solution.
Since nn must be an integer count of tokens, n=9n = 9 (rejecting n=103n = \frac{10}{3}).
The number of tokens nn must be a whole number.

Anahtar Kavram

Probability of Dependent Events (Sampling Without Replacement)
Soru 1060Soru

A researcher recorded six test measurements arranged in ascending order: 1,2,8,x,y,151, 2, 8, x, y, 15. If the unique mode of the data set is 88 and the arithmetic mean of the measurements is equal to their median, what is the value of yy?

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Cevap: 14

Cevap

14
Because the data set is arranged in ascending order, the elements satisfy 128xy151 \le 2 \le 8 \le x \le y \le 15. For 88 to be the unique mode, 88 must appear more times than any other number, which forces x=8x = 8. The median of a 66-element set is the average of the 3rd3^{\text{rd}} and 4th4^{\text{th}} elements, which are both 88, making the median 88. Setting the mean 1+2+8+8+y+156=34+y6\frac{1 + 2 + 8 + 8 + y + 15}{6} = \frac{34 + y}{6} equal to 88 gives 34+y=4834 + y = 48, which yields y=14y = 14. Since 814158 \le 14 \le 15, this maintains the ascending order and unique mode condition.

Adım Adım Çözüm

1
Determine the value of x
x = 8
The set is given in ascending order (1 <= 2 <= 8 <= x <= y <= 15). For 8 to be the unique mode, 8 must appear at least twice, which requires x = 8.
2
Calculate the median of the data set
Median = 8
With 6 elements, the median is the average of the 3rd and 4th elements: (8 + 8) / 2 = 8.
3
Set up the equation for the arithmetic mean
(34 + y) / 6 = 8
The sum of the six numbers is 1 + 2 + 8 + 8 + y + 15 = 34 + y. Since the mean equals the median, the mean must equal 8.
4
Solve for y
y = 14
Multiplying both sides by 6 gives 34 + y = 48, so y = 48 - 34 = 14.

Anahtar Kavram

Using statistical properties (mean, median, mode) of an ordered set to determine unknown values
Tahmini Süre:1m 15s
ÖncekiSayfa 53 / 110Sonraki
Tüm alıştırma soruları — GMAT | Examkin