Tüm alıştırma soruları

2195 soru

Soru 1061Soru

An architectural firm offers custom townhouse design packages created by making sequential choices across three stages: Exterior Facade Material (4 choices), Floor Plan Layout (5 choices), and Interior Lighting Scheme (6 choices).

However, two design constraints apply:
1. If the first exterior facade material option is chosen, the fifth floor plan layout option cannot be selected.
2. The sixth interior lighting scheme option can only be selected if the fifth floor plan layout option is chosen.

How many different valid townhouse design packages can a client create?

Cevabı ve açıklamayı göster

Cevap: 98

Cevap

The total number of valid townhouse design packages is 98.
The solution splits the decision process into two mutually exclusive scenarios based on whether the 5th layout option is chosen. In Case 1 (5th layout chosen), 3 facade choices × 1 layout choice × 6 lighting choices yields 18 valid packages. In Case 2 (1st through 4th layout chosen), 4 facade choices × 4 layout choices × 5 lighting choices yields 80 valid packages. Adding these mutually exclusive totals gives 18 + 80 = 98 valid design packages.

Adım Adım Çözüm

1
Analyze the decision tree by splitting into mutually exclusive cases based on whether Floor Plan Layout Option 5 is selected.
Two distinct cases are established: Case 1 (Layout Option 5 selected) and Case 2 (Layout Options 1–4 selected).
The constraints depend directly on whether Floor Plan Layout Option 5 is chosen.
2
Calculate valid combinations for Case 1 (Layout Option 5 selected).
Facade choices = 3 (excluding Option 1), Layout choices = 1 (Option 5), Lighting choices = 6 (including Option 6). Total = 3 × 1 × 6 = 18 packages.
Constraint 1 eliminates 1 facade option, while Constraint 2 allows all 6 lighting options.
3
Calculate valid combinations for Case 2 (Layout Option 5 NOT selected).
Facade choices = 4, Layout choices = 4 (Options 1–4), Lighting choices = 5 (excluding Option 6). Total = 4 × 4 × 5 = 80 packages.
Constraint 1 does not apply, but Constraint 2 prevents selecting Lighting Option 6.
4
Sum the valid outcomes from both mutually exclusive cases.
18 + 80 = 98 valid packages.
By the Addition Principle of Counting, non-overlapping cases are added together.

Anahtar Kavram

Fundamental Counting Principle with Constrained Cases
Soru 1062Soru

A software consultant charges an enterprise client a fixed setup fee of 200200 dollars plus an hourly rate of rr dollars for 1-on-1 technical training. For team training workshops, the consultant charges a fixed setup fee of 400400 dollars plus an hourly rate that is 50%50\% higher than the 1-on-1 rate. If the client was billed a total of 2,4002,400 dollars for 1212 hours of 1-on-1 training and 88 hours of team training workshops, what is the value of rr?

Cevabı ve açıklamayı göster

Cevap: 75

Cevap

The individual hourly rate rr is 7575 dollars per hour.
The total cost consists of fixed setup fees (200+400=600200 + 400 = 600) and variable hourly charges (12r+8×1.5r=24r12r + 8 \times 1.5r = 24r). Setting the total cost 600+24r600 + 24r equal to 2,4002,400 and solving for rr yields r=75r = 75.

Adım Adım Çözüm

1
Formulate the total cost equation for the 1-on-1 technical training.
Cost1-on-1=200+12r\text{Cost}_{\text{1-on-1}} = 200 + 12r
The client pays a 200200 dollar setup fee plus rr dollars for each of the 1212 hours.
2
Determine the hourly rate and total cost equation for the team training workshops.
Hourly Rateteam=1.5r\text{Hourly Rate}_{\text{team}} = 1.5r, so Costteam=400+8(1.5r)=400+12r\text{Cost}_{\text{team}} = 400 + 8(1.5r) = 400 + 12r
The team hourly rate is 50%50\% greater than rr, which equals r+0.5r=1.5rr + 0.5r = 1.5r. Multiplying by 88 hours yields 12r12r in hourly fees, plus the 400400 dollar setup fee.
3
Combine the total costs to create a single linear equation in terms of rr.
(200+12r)+(400+12r)=2400    600+24r=2400(200 + 12r) + (400 + 12r) = 2400 \implies 600 + 24r = 2400
The total amount billed across both services is given as 2,4002,400 dollars.
4
Isolate the variable rr and calculate its numerical value.
24r=1800    r=7524r = 1800 \implies r = 75
Subtracting 600600 from both sides gives 24r=180024r = 1800, and dividing by 2424 yields r=75r = 75.

Anahtar Kavram

Linear Equations in One and Two Variables
Tahmini Süre:1m 30s
Soru 1063Soru

If 2a+b=122^{a+b} = 12 and 2ab=32^{a-b} = 3, what is the value of 22a22b2^{2a} - 2^{2b}?

Cevabı ve açıklamayı göster

Cevap: 32

Cevap

32
Multiplying the equations gives (2a+b)(2ab)=22a=12×3=36(2^{a+b})(2^{a-b}) = 2^{2a} = 12 \times 3 = 36. Dividing the first equation by the second gives 2a+b2ab=22b=123=4\frac{2^{a+b}}{2^{a-b}} = 2^{2b} = \frac{12}{3} = 4. Subtracting the two values gives 22a22b=364=322^{2a} - 2^{2b} = 36 - 4 = 32.

Adım Adım Çözüm

1
Multiply the given exponent expressions to evaluate 22a2^{2a}.
22a=(2a+b)(2ab)=12×3=362^{2a} = (2^{a+b})(2^{a-b}) = 12 \times 3 = 36.
According to the product rule of exponents, 2x2y=2x+y2^{x} \cdot 2^{y} = 2^{x+y}. Adding (a+b)+(ab)(a+b) + (a-b) yields 2a2a.
2
Divide the first exponent expression by the second to evaluate 22b2^{2b}.
22b=2a+b2ab=123=42^{2b} = \frac{2^{a+b}}{2^{a-b}} = \frac{12}{3} = 4.
According to the quotient rule of exponents, 2x2y=2xy\frac{2^{x}}{2^{y}} = 2^{x-y}. Subtracting (a+b)(ab)(a+b) - (a-b) yields 2b2b.
3
Calculate the value of 22a22b2^{2a} - 2^{2b}.
364=3236 - 4 = 32.
Substitute the evaluated components 22a=362^{2a} = 36 and 22b=42^{2b} = 4 into the expression.

Anahtar Kavram

Exponent Operations (Product and Quotient Rules)
Tahmini Süre:1m 30s
Soru 1064Soru

A dataset XX consists of five positive integers with a mean of 12, a median of 12, a unique mode of 12, and a range of 8. If σ2\sigma^2 represents the variance (the square of the standard deviation) of dataset XX, what is the maximum possible value of σ2\sigma^2?

Cevabı ve açıklamayı göster

Cevap: 7.67.6

Cevap

The maximum possible value of the variance σ2\sigma^2 is 7.67.6.
To maximize variance σ2=15(xi12)2\sigma^2 = \frac{1}{5}\sum (x_i - 12)^2, data points must be placed as far from the mean of 12 as possible. For five ordered positive integers abcdea \le b \le c \le d \le e, the mean of 12 gives a+b+c+d+e=60a+b+c+d+e=60, the median of 12 gives c=12c=12, and the range of 8 gives e=a+8e=a+8. Substituting yields 2a+b+d=402a+b+d=40. Since b12b \le 12 and da+8d \le a+8, b+da+20b+d \le a+20, leading to 3a203a \ge 20, so a7a \ge 7. Testing a=7a=7 gives e=15e=15 and b+d=26b+d=26. To keep 12 as the unique mode, b=12b=12 and d=14d=14, forming dataset {7,12,12,14,15}\{7, 12, 12, 14, 15\}. The squared deviations from 12 are (5)2+02+02+22+32=25+0+0+4+9=38(-5)^2 + 0^2 + 0^2 + 2^2 + 3^2 = 25 + 0 + 0 + 4 + 9 = 38. Dividing by 5 yields the maximum variance of 7.67.6.

Adım Adım Çözüm

1
Express the five integers in ascending order and set up equations from given statistics.
Let the integers be abcdea \le b \le c \le d \le e. Mean = 12 implies a+b+c+d+e=60a + b + c + d + e = 60. Median = 12 implies c=12c = 12. Range = 8 implies e=a+8e = a + 8.
Translating statistical measures into algebraic constraints provides the boundary conditions for the dataset.
2
Substitute known values into the sum equation and determine constraints on aa.
a+b+12+d+(a+8)=60    2a+b+d=40a + b + 12 + d + (a + 8) = 60 \implies 2a + b + d = 40. Since b12b \le 12 and de=a+8d \le e = a + 8, we have b+da+20b + d \le a + 20. Thus 2a+(a+20)40    3a20    a72a + (a + 20) \ge 40 \implies 3a \ge 20 \implies a \ge 7.
Determining the minimum value of aa is critical because smaller values of aa allow larger deviations from the mean of 12.
3
Evaluate valid dataset configurations for a=7a = 7 that satisfy the unique mode condition.
If a=7a = 7, then e=15e = 15, and b+d=26b + d = 26. With b12b \le 12 and d15d \le 15, and requiring 12 to be the unique mode, the only valid integer set is {7,12,12,14,15}\{7, 12, 12, 14, 15\}.
The set must maintain 12 as the unique mode while maximizing the dispersion of values.
4
Calculate the variance σ2\sigma^2 for the set {7,12,12,14,15}\{7, 12, 12, 14, 15\}.
Deviations from 12 are 5,0,0,2,3-5, 0, 0, 2, 3. Squared deviations are 25,0,0,4,925, 0, 0, 4, 9. Sum of squared deviations = 38. Variance σ2=385=7.6\sigma^2 = \frac{38}{5} = 7.6.
Variance is defined as the mean of the squared deviations from the dataset mean.

Anahtar Kavram

Properties of Variance and Standard Deviation under Range and Central Tendency Constraints
Soru 1065Soru

Linguists examining language divergence have long relied on glottochronology—a quantitative method that assumes a constant, uniform rate of basic vocabulary replacement over time—to construct ancestral phylogenetic trees. Modeled after radiocarbon dating, classic glottochronology posits that core lexical items decay at a predictable rate across all human languages, allowing researchers to estimate the precise date when daughter languages split from a common ancestor.

However, recent computational analyses of large-scale cross-linguistic databases have exposed fundamental limitations in this constant-rate assumption. Lexical retention rates vary dramatically depending on demographic factors, such as population size and social stratification, as well as external contact dynamics like trade and conquest. For instance, small isolated speech communities often undergo rapid lexical turnover due to founder effects or taboo-driven word substitution, whereas dense trade networks can enforce vocabulary stabilization across unrelated language families. By treating vocabulary decay as a universal constant, traditional glottochronology systematically miscalculates divergence timelines, frequently underestimating the antiquity of isolated languages while overestimating that of highly networked groups.

Rather than discarding quantitative phylogenetics entirely, contemporary linguists advocate integrating relaxed clock models borrowed from evolutionary biology. These probabilistic models allow mutation rates to fluctuate across tree branches according to socio-demographic covariates. By replacing the rigid assumption of uniform decay with flexible, parameter-driven rate variations, relaxed clock methodologies reconcile computational precision with the empirical complexities of historical language shift.

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

Cevabı ve açıklamayı göster

Cevap: To critique a traditional methodology for dating language divergence and present a modified quantitative approach that addresses its flaws.

Cevap

The primary purpose of the passage is to critique a traditional methodology for dating language divergence and present a modified quantitative approach that addresses its flaws.
The correct option captures the full scope of the passage by recognizing both the evaluation/critique of traditional glottochronology (paragraphs 1 and 2) and the introduction of relaxed clock models as a refined quantitative solution (paragraph 3).

Adım Adım Çözüm

1
Analyze the structural organization and thematic progression of each paragraph.
Paragraph 1 introduces traditional glottochronology and its constant-rate assumption. Paragraph 2 introduces a structural pivot ('However...') detailing empirical flaws in this assumption. Paragraph 3 offers a resolution ('Rather than discarding...') by proposing relaxed clock models.
Tracking structural pivots isolates the author's overall objective from supporting background context.
2
Synthesize the main thesis that spans the entire passage.
The author aims to show why traditional glottochronology is flawed while offering a modernized quantitative alternative (relaxed clock models).
The correct primary purpose choice must encompass the full arc of the passage—both the critique of the old method and the introduction of the new method.
3
Evaluate the option choices against the synthesized main thesis to eliminate invalid distractors.
Options that focus strictly on specific examples, overstate the tone, mischaracterize the final solution, or make unwarranted extrapolations are eliminated.
Ensures the selected answer captures scope and tone accurately without falling into common Reading Comprehension trap structures.

Anahtar Kavram

Identifying Primary Purpose and Main Idea
Tahmini Süre:2m 30s
Soru 1066Soru

For decades, theoretical models in evolutionary biology posited that reciprocal altruism—actions that temporarily reduce an organism's fitness to enhance another's with the expectation of future reciprocation—could evolve among non-kin only in stable populations possessing high cognitive capacity for individual recognition. However, recent empirical studies of microbial communities reveal widespread cross-feeding cooperation among genetically distinct bacterial strains that lack memory or cognitive processing. To reconcile this theoretical paradox, contemporary researchers have shifted focus from individual cognitive tracking to spatial self-organization within physical microenvironments. By constructing mathematical simulations of biofilm architecture, evolutionary biologists demonstrated that physical viscosity and localized resource consumption naturally segregate cooperative strains into dense spatial clusters. Within these micro-spatial clusters, the secretor of a costly metabolic byproduct reaps a disproportionate share of the local benefit before the metabolite diffuses to non-cooperative "cheater" strains. Thus, spatial structuring acts as a passive mechanism that produces the same evolutionary stability as cognitive reciprocity without requiring individual recognition. Consequently, the paradigm governing non-kin cooperation is expanding: spatial dynamics are no longer viewed merely as secondary background conditions, but as primary mechanisms that lower the cognitive threshold required for altruistic traits to persist.

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

Cevabı ve açıklamayı göster

Cevap: To describe how recent empirical findings and theoretical shifts have expanded the scientific understanding of how non-kin cooperation can evolve.

Cevap

The primary purpose of the passage is to describe how recent empirical findings and theoretical shifts have expanded the scientific understanding of how non-kin cooperation can evolve.
The correct answer accurately synthesizes the full development of the passage. The text begins by establishing a classic model of reciprocal altruism, introduces a microbial counter-example that presents a theoretical paradox, details how spatial self-organization reconciles this paradox, and concludes by stating that the broader paradigm governing non-kin cooperation is expanding.

Adım Adım Çözüm

1
Analyze passage structure and track key transitions
Identified opening premise (classic cognitive reciprocity model), pivot marker ('However'), paradox (microbial cooperation without cognition), resolution ('To reconcile...'), and final synthesis ('Consequently, the paradigm... is expanding').
Tracking structural transitions isolates the author's overarching argument from supporting details.
2
Synthesize the main idea
The author introduces a theoretical paradox in non-kin altruism and explains how incorporating spatial dynamics expands the existing scientific framework.
The primary purpose must encompass the entire scope of the passage rather than focusing on isolated paragraph details.
3
Evaluate option choices against the synthesized main idea
Selected the option stating that the passage describes how empirical findings and theoretical shifts expand the scientific understanding of non-kin cooperation.
This option accurately reflects both the scope and neutral academic stance of the passage without exaggerating claim boundaries or elevating secondary details.

Anahtar Kavram

Identifying Primary Purpose via Structural Pivot Analysis
Tahmini Süre:2m 30s
Soru 1067Soru

Read the following short passage and match each structural pivot word or transition phrase (on the left) to its precise rhetorical function within the passage's argument trajectory (on the right):

"Proponents of early industrial mechanization argued that automated spinning frame technology would immediately reduce labor costs across textile manufacturing. However, contemporary records indicate that initial capital outlay for machinery maintenance offset short-term wage savings. Furthermore, while factory owners anticipated rapid adoption, skilled artisans organized widespread boycotts that delayed implementation for nearly a decade."

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

"However"
"Furthermore"
"while"

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Each structural pivot is matched to its corresponding rhetorical function: 'However' introduces counter-evidence qualifying the cost claim, 'Furthermore' signals an additional supporting point detailing obstacles, and 'while' establishes a concession contrasting expectations with reality.
The correct matches reflect how structural transitions organize argument flow: 'However' introduces qualifying counter-evidence to the initial claim, 'Furthermore' adds reinforcing evidence of implementation obstacles, and 'while' frames a concession between expectations and historical facts.

Adım Adım Çözüm

1
Analyze the role of the first pivot 'However'
Identified that 'However' directly contrasts the assertion of immediate cost savings with evidence of high maintenance costs.
Contrast words like 'However' signal a turn from one viewpoint or claim to opposing or qualifying evidence.
2
Analyze the role of the additive transition 'Furthermore'
Identified that 'Furthermore' introduces a second reason why adoption was difficult (artisan boycotts).
Additive transitions like 'Furthermore' build upon previous evidence without reversing direction.
3
Analyze the subordinate clause transition 'while'
Identified that 'while' acknowledges the expectation of rapid adoption as a background concession before presenting the actual delay.
Subordinating conjunctions like 'while' frame concessions to emphasize the main clause's contrasting point.

Anahtar Kavram

Tracking Structural Pivots and Rhetorical Transitions
Soru 1068Soru

A committee of 1010 members consists of 55 senior directors and 55 junior associates. If 33 committee members are selected at random one after another without replacement, what is the probability that exactly 22 of the selected members are senior directors?

Cevabı ve açıklamayı göster

Cevap: 512\frac{5}{12}

Cevap

The probability that exactly 22 of the selected members are senior directors is 512\frac{5}{12}.
The correct answer is found by taking into account that the selections are dependent events without replacement. The probability of selecting senior directors on the first two draws and a junior associate on the third is 510×49×58=536\frac{5}{10} \times \frac{4}{9} \times \frac{5}{8} = \frac{5}{36}. Because there are 33 possible mutually exclusive orders to select 22 senior directors and 11 junior associate, multiplying 536\frac{5}{36} by 33 gives the final probability of 512\frac{5}{12}.

Adım Adım Çözüm

1
Calculate the probability of drawing Senior, Senior, Junior in that specific order without replacement.
P(Senior1)×P(Senior2Senior1)×P(Junior3Senior1Senior2)=510×49×58=100720=536P(\text{Senior}_1) \times P(\text{Senior}_2 \mid \text{Senior}_1) \times P(\text{Junior}_3 \mid \text{Senior}_1 \cap \text{Senior}_2) = \frac{5}{10} \times \frac{4}{9} \times \frac{5}{8} = \frac{100}{720} = \frac{5}{36}
Because draws are made without replacement, the sample space and favorable outcomes decrease with each draw.
2
Determine the number of distinct orderings of 22 Senior directors and 11 Junior associate.
(32)=3\binom{3}{2} = 3 orderings: (Senior, Senior, Junior), (Senior, Junior, Senior), and (Junior, Senior, Senior).
The question asks for exactly 22 senior directors regardless of the order in which they are selected.
3
Multiply the single-sequence probability by the total number of valid orderings.
3×536=1536=5123 \times \frac{5}{36} = \frac{15}{36} = \frac{5}{12}
Since each distinct ordering is mutually exclusive and has the same probability, the total probability is the sum across all 33 orderings.

Anahtar Kavram

Probability of Dependent Events (Sampling Without Replacement)
Soru 1069Soru

A specialty audio equipment distributor purchased a batch of 4040 high-fidelity headphones for a total cost of $10,000\$10,000. The distributor marked up the wholesale cost price of each unit by 60%60\% to establish its list price. During a seasonal promotion, 3030 of the headphones were sold at a 20%20\% discount off the list price. The remaining 1010 headphones were sold during an end-of-season clearance at a 40%40\% discount off the list price. What was the distributor's net profit percentage on the total purchase of all 4040 headphones?

Cevabı ve açıklamayı göster

Cevap: 20%20\%

Cevap

The distributor's net profit percentage on the total purchase is 20%20\%.
To find the overall net profit percentage, calculate total revenue across all sales and compare it to total cost. The cost per unit is $10,00040=$250\frac{\$10,000}{40} = \$250. Marking up by 60%60\% yields a list price of $250×1.60=$400\$250 \times 1.60 = \$400. The 3030 units sold at a 20%20\% discount generated 30×($400×0.80)=$9,60030 \times (\$400 \times 0.80) = \$9,600. The remaining 1010 units sold at a 40%40\% discount generated 10×($400×0.60)=$2,40010 \times (\$400 \times 0.60) = \$2,400. Total revenue was $9,600+$2,400=$12,000\$9,600 + \$2,400 = \$12,000. Net profit is $12,000$10,000=$2,000\$12,000 - \$10,000 = \$2,000. Expressed as a percentage of total cost, $2,000$10,000×100%=20%\frac{\$2,000}{\$10,000} \times 100\% = 20\%.

Adım Adım Çözüm

1
Calculate the wholesale cost price per unit and the list price per unit.
Wholesale cost per unit = $10,00040=$250\frac{\$10,000}{40} = \$250. List price per unit = $250×(1+0.60)=$400\$250 \times (1 + 0.60) = \$400.
Establishing the individual cost and marked-up retail base price is necessary to calculate discount prices.
2
Calculate the selling price and revenue for the two sales batches.
Promotional price = $400×(10.20)=$320\$400 \times (1 - 0.20) = \$320. Revenue from first batch = 30×$320=$9,60030 \times \$320 = \$9,600. Clearance price = $400×(10.40)=$240\$400 \times (1 - 0.40) = \$240. Revenue from second batch = 10×$240=$2,40010 \times \$240 = \$2,400.
Determining total revenue requires evaluating each portion of inventory sold at its respective discounted price.
3
Sum total revenue and compute total net profit.
Total Revenue = $9,600+$2,400=$12,000\$9,600 + \$2,400 = \$12,000. Total Net Profit = $12,000$10,000=$2,000\$12,000 - \$10,000 = \$2,000.
Net profit is the absolute difference between total revenue generated and total wholesale cost incurred.
4
Compute the net profit percentage.
Net Profit Percentage = ($2,000$10,000)×100%=20%\left(\frac{\$2,000}{\$10,000}\right) \times 100\% = 20\%.
Profit percentage must always use the total original cost price as its base.

Anahtar Kavram

Calculating overall profit percentage across multi-tiered pricing by finding total revenue relative to original cost base.
Soru 1070Soru

If xx is a positive real number such that x2x=3\sqrt{x} - \frac{2}{\sqrt{x}} = 3, what is the value of x+4xx + \frac{4}{x}?

Cevabı ve açıklamayı göster

Cevap: 13

Cevap

The value of x+4xx + \frac{4}{x} is 13.
Squaring both sides of x2x=3\sqrt{x} - \frac{2}{\sqrt{x}} = 3 gives (x)22(x)(2x)+(2x)2=9(\sqrt{x})^2 - 2(\sqrt{x})(\frac{2}{\sqrt{x}}) + (\frac{2}{\sqrt{x}})^2 = 9, which simplifies to x4+4x=9x - 4 + \frac{4}{x} = 9. Adding 4 to both sides yields x+4x=13x + \frac{4}{x} = 13. Thus, the option with value 13 is correct.

Adım Adım Çözüm

1
Square both sides of the given equation x2x=3\sqrt{x} - \frac{2}{\sqrt{x}} = 3.
(x2x)2=32{\left(\sqrt{x} - \frac{2}{\sqrt{x}}\right)}^2 = 3^2
Squaring both sides relates the terms x\sqrt{x} and 2x\frac{2}{\sqrt{x}} to xx and 4x\frac{4}{x}.
2
Expand the left side using the perfect square identity (ab)2=a22ab+b2(a - b)^2 = a^2 - 2ab + b^2.
(x)22(x)(2x)+(2x)2=9(\sqrt{x})^2 - 2\left(\sqrt{x}\right)\left(\frac{2}{\sqrt{x}}\right) + \left(\frac{2}{\sqrt{x}}\right)^2 = 9
Applying the algebraic identity expands the squared expression correctly.
3
Simplify the terms on the left side.
x4+4x=9x - 4 + \frac{4}{x} = 9
The product x2x\sqrt{x} \cdot \frac{2}{\sqrt{x}} simplifies to 22, making the middle term 22=4-2 \cdot 2 = -4.
4
Add 4 to both sides to isolate x+4xx + \frac{4}{x}.
x+4x=13x + \frac{4}{x} = 13
Isolating the target algebraic expression yields the final value.

Anahtar Kavram

Squaring binomial radical expressions using the identity (ab)2=a22ab+b2(a - b)^2 = a^2 - 2ab + b^2.
Soru 1071Soru

In January, a logistics company's total monthly operational expenditure for its electric delivery fleet was $C\$C. In February, the number of vehicles in the fleet increased by 25%25\%, while the monthly operational cost per vehicle decreased by 10%10\% due to optimized charging schedules. If the fleet's total operational expenditure in February was $33,750\$33,750, what was the total operational expenditure, in dollars, in January?

Cevabı ve açıklamayı göster

Cevap: 30000

Cevap

The total operational expenditure in January was $30,000.
The total expenditure is the product of the number of vehicles and the cost per vehicle. An increase of 25%25\% in fleet size introduces a multiplier of 1.251.25, while a 10%10\% decrease in unit cost introduces a multiplier of 0.900.90. The net multiplier for the total expenditure is 1.25×0.90=1.1251.25 \times 0.90 = 1.125 (or 98\frac{9}{8}). Dividing the February total of $33,750\$33,750 by 1.1251.125 yields the January expenditure of $30,000\$30,000.

Adım Adım Çözüm

1
Define variables for January's components and express January's total cost
Let NN be the number of vehicles in January and VV be the operational cost per vehicle in January. Total January expenditure C=N×VC = N \times V.
Total cost is the product of quantity and unit cost.
2
Determine the updated fleet size and unit cost for February
February fleet size =N×(1+0.25)=1.25N=54N= N \times (1 + 0.25) = 1.25 N = \frac{5}{4} N. February unit cost =V×(10.10)=0.90V=910V= V \times (1 - 0.10) = 0.90 V = \frac{9}{10} V.
A 25%25\% increase corresponds to a factor of 1.251.25, and a 10%10\% decrease corresponds to a factor of 0.900.90.
3
Calculate February's total expenditure in terms of CC
February total cost =(54N)×(910V)=4540NV=1.125C=98C= \left(\frac{5}{4} N\right) \times \left(\frac{9}{10} V\right) = \frac{45}{40} NV = 1.125 C = \frac{9}{8} C.
The total cost in February is the product of the updated fleet size and the updated unit cost.
4
Solve for January's total cost CC
98C=33,750    C=33,750×89=3,750×8=30,000\frac{9}{8} C = 33,750 \implies C = 33,750 \times \frac{8}{9} = 3,750 \times 8 = 30,000.
Divide February's known cost by the net multiplier 1.1251.125 (or 98\frac{9}{8}) to reverse the percent change.

Anahtar Kavram

Net percentage change on a product of variables and reverse calculation
Soru 1072Soru

An express cargo train leaves Station A heading toward Station B at a constant speed of 5050 miles per hour. At the exact same time, a local freight train leaves Station B heading toward Station A along a parallel track at a constant speed of 3030 miles per hour. If the total distance between Station A and Station B is 360360 miles, how many miles from Station A will the two trains meet?

Cevabı ve açıklamayı göster

Cevap: 225

Cevap

The two trains will meet 225 miles from Station A.
When two objects move directly toward each other, their rate of approach is the sum of their speeds (50+30=8050 + 30 = 80 mph). Covering the total distance of 360360 miles at a rate of 8080 mph takes 4.54.5 hours. In 4.54.5 hours, the train traveling from Station A at 5050 mph covers a distance of 50×4.5=22550 \times 4.5 = 225 miles.

Adım Adım Çözüm

1
Calculate the combined relative speed of both trains.
Relative speed = 50+30=8050 + 30 = 80 miles per hour.
Since the two trains move toward each other, their relative rate of convergence is the sum of their individual speeds.
2
Calculate the time required for the two trains to meet.
Time t=360 miles80 mph=4.5t = \frac{360 \text{ miles}}{80 \text{ mph}} = 4.5 hours.
Time equals total distance divided by combined relative speed.
3
Calculate the distance covered by the express train from Station A.
Distance = 50 mph×4.5 hours=22550 \text{ mph} \times 4.5 \text{ hours} = 225 miles.
Distance equals the rate of the train departing Station A multiplied by the elapsed time.

Anahtar Kavram

Relative speed of converging objects moving toward each other
Tahmini Süre:1m 30s
Soru 1073Soru

For much of the twentieth century, economic historians attributed the rapid post-WWII growth of agricultural productivity in Western Europe almost entirely to state-funded mechanization programs. Under this traditional model, centralized subsidies allowed farmers to adopt heavy machinery and automated harvesters, drastically reducing manual labor requirements and boosting crop yields per acre. Scholars frequently cited official government expenditure logs and parliamentary policy documents as definitive evidence that top-down fiscal intervention was the primary engine driving technological adoption across modernizing rural economies.

However, recent archival analyses of regional farming cooperatives challenge this state-centric narrative. These historical re-evaluations demonstrate that decentralized informal credit networks, organized by local agrarian guilds prior to major state intervention, had already financed widespread equipment modernization. While state subsidies undeniably accelerated the pace of capital accumulation in the late 1950s, nevertheless, they largely reinforced technological trajectories that independent cooperative networks had established decades earlier.

Furthermore, quantitative reassessments of farm productivity metrics reveal that regions relying predominantly on local cooperative capital achieved yield increases comparable to those receiving heavy state intervention. Consequently, attributing the primary catalyst of European agricultural transformation solely to central government policy misrepresents the foundational role of grassroots financial institutions.

In the context of the passage as a whole, the transition introduced by the word "However" at the beginning of the second paragraph serves primarily to:

Cevabı ve açıklamayı göster

Cevap: introduce a counter-perspective that re-evaluates the primary driver of agricultural modernization described in the first paragraph.

Cevap

The transition introduced by the word 'However' serves primarily to introduce a counter-perspective that re-evaluates the primary driver of agricultural modernization described in the first paragraph.
The first paragraph establishes the traditional view that post-WWII European agricultural productivity was driven by state-funded subsidies. The word 'However' at the start of the second paragraph introduces a structural pivot, shifting the argument to present recent archival evidence showing that informal credit networks had already established modernization prior to major state intervention. Thus, the transition introduces a counter-perspective that re-evaluates the primary driver of modernization.

Adım Adım Çözüm

1
Analyze the structural role of the first paragraph
The first paragraph outlines a traditional historical narrative attributing agricultural productivity growth primarily to top-down government subsidies.
Establishing the initial baseline viewpoint is necessary to understand what the pivot contrasts against.
2
Identify the structural pivot and analyze the second paragraph
The marker 'However' shifts the passage to challenge the traditional view by presenting evidence of pre-existing, decentralized informal credit networks.
Pivot words like 'However' signal a shift in rhetorical direction or viewpoint attribution.
3
Evaluate the author's qualification within the pivot
The author acknowledges that state subsidies accelerated growth ('While state subsidies undeniably accelerated... nevertheless...'), meaning the pivot introduces a nuanced re-evaluation rather than a total denial of state impact.
Accounting for structural qualifiers prevents choosing extreme or one-sided options.

Anahtar Kavram

Tracking Structural Pivots and Transitions
Soru 1074Soru

If aa, bb, and cc are non-zero real numbers such that ab2c3<0a b^2 c^3 < 0 and ab>0\frac{a}{b} > 0, which of the following expressions MUST be negative?

Cevabı ve açıklamayı göster

Cevap: a2bca^2 b c

Cevap

The expression a2bca^2 b c must be negative.
For any non-zero real number aa, the term a2a^2 is strictly positive. The given conditions show that b2>0b^2 > 0, which simplifies ab2c3<0a b^2 c^3 < 0 to ac<0a c < 0, proving aa and cc have opposite signs. Furthermore, ab>0\frac{a}{b} > 0 means aa and bb have the same sign. Combining these facts shows that bb and cc must always have opposite signs, so bc<0b c < 0. Therefore, a2bc=(a2)(bc)=(+)×()<0a^2 b c = (a^2)(b c) = (+) \times (-) < 0 in all valid cases.

Adım Adım Çözüm

1
Analyze the sign implication of ab2c3<0a b^2 c^3 < 0.
ac<0a c < 0, meaning aa and cc have opposite signs.
Because b0b \neq 0, b2b^2 is strictly positive (b2>0b^2 > 0). Dividing ab2c3<0a b^2 c^3 < 0 by b2b^2 yields ac3<0a c^3 < 0. Since c3c^3 has the exact same sign as cc, it follows that ac<0a c < 0.
2
Analyze the sign implication of ab>0\frac{a}{b} > 0.
aa and bb must have the same sign (ab>0a b > 0).
A quotient of two non-zero numbers is positive if and only if both numbers have the same sign.
3
Combine sign conditions to evaluate the possible cases for a,b,ca, b, c.
Either Case 1: a>0,b>0,c<0a > 0, b > 0, c < 0, or Case 2: a<0,b<0,c>0a < 0, b < 0, c > 0.
If a>0a > 0, then b>0b > 0 (from step 2) and c<0c < 0 (from step 1). If a<0a < 0, then b<0b < 0 (from step 2) and c>0c > 0 (from step 1).
4
Test the expression a2bca^2 b c under both cases.
In Case 1: (+)2(+)()=()(+)^2 \cdot (+) \cdot (-) = (-). In Case 2: ()2()(+)=()(-)^2 \cdot (-) \cdot (+) = (-). Thus a2bc<0a^2 b c < 0 always.
Since a2>0a^2 > 0 for all non-zero real numbers aa, and bb and cc have opposite signs in every valid scenario (bc<0b c < 0), the product a2(bc)a^2 (b c) is always strictly negative.

Anahtar Kavram

Deducing signs of variables using exponent rules and inequalities
Tahmini Süre:1m 30s
Soru 1075Soru

Historically, economic historians attributed the rapid industrial expansion of early nineteenth-century New England primarily to the introduction of power looms and the consolidation of textile manufacturing under a single roof. According to this traditional view, technological centralization drastically reduced transaction costs and boosted labor efficiency, thereby single-handedly creating the competitive edge that propelled the region's commercial dominance.

However, recent archival research into merchant account ledgers paints a far more nuanced picture. While mechanized weaving undeniably enhanced throughput, this technological leap coincided with a fundamental restructuring of regional credit networks and maritime trade routes. In fact, without the simultaneous emergence of flexible merchant banking syndicates willing to absorb seasonal price volatility in raw cotton, large-scale factory operations would have collapsed under the weight of inventory holding costs. Thus, the physical centralization of production was not the primary driver of industrial growth, but rather a secondary adaptation dependent on financial innovation.

Nevertheless, one must caution against overcorrecting by viewing financial capital as the sole catalyst of New England's transformation. Contrary to the assertions of some revisionist scholars who diminish the role of shop-floor technical ingenuity, small-scale machinery modifications devised by local artisans were essential in adapting European machine designs to coarse American fibers. Ultimately, the region’s economic trajectory was shaped neither by isolated technological breakthroughs nor by financial systems alone, but by a complex, interdependent synthesis of institutional finance and decentralized technical adaptation.

Which of the following best describes the structural development of the author's argument across the passage?

Cevabı ve açıklamayı göster

Cevap: It outlines a traditional historical perspective, introduces recent evidence to challenge its central thesis, and subsequently qualifies that challenge to present an integrative conclusion.

Cevap

The argument begins by outlining a traditional perspective, uses new evidence to challenge that perspective, and then qualifies the challenge to arrive at a synthesized conclusion.
The correct response correctly traces the three-stage structure of the passage: starting with the traditional explanation of New England's industrial growth (Paragraph 1), shifting via the transition word 'However' to present new archival evidence favoring financial innovation (Paragraph 2), and shifting once more via 'Nevertheless' to qualify that financial claim and synthesize both technology and finance into an integrative final conclusion (Paragraph 3).

Adım Adım Çözüm

1
Analyze Paragraph 1 to identify the initial premise and viewpoint.
Paragraph 1 lays out a traditional historical view holding that technological centralization (power looms) was the single main cause of industrial expansion.
Establishing the baseline traditional viewpoint helps track where contrastive pivots will shift the argument.
2
Locate and evaluate the first structural pivot marker in Paragraph 2.
The pivot marker 'However' shifts the argument from the traditional view to revisionist archival evidence showing that financial innovation was crucial.
Pivot words signal changes in argument trajectory or the introduction of opposing viewpoints.
3
Locate and evaluate the second structural pivot marker in Paragraph 3.
The pivot markers 'Nevertheless' and 'Contrary to' signal a qualification of the revisionist view, warning against viewing financial capital as the sole catalyst and bringing back the importance of artisan modifications.
Secondary pivots frequently refine or restrict previous broad assertions to build a nuanced stance.
4
Synthesize the overall trajectory and compare against the choices.
The structure is: Traditional view → Refutation via new evidence → Qualification of refutation → Integrated synthesis.
Matching the passage roadmap to the choice that accurately captures all structural stages reveals the correct response.

Anahtar Kavram

Tracking Structural Pivots and Transitions
Tahmini Süre:2m 30s
Soru 1076Soru

A data set consists of 77 positive integers. The smallest integer in the set is 44, the range of the set is 1919, the median is 1212, and the set has a unique mode of 88. What is the maximum possible arithmetic mean of the 77 integers?

Cevabı ve açıklamayı göster

Cevap: 14

Cevap

The maximum possible arithmetic mean of the 7 integers is 14.
The correct answer of 14 is obtained by setting up the 7 ordered integers as x1,x2,x3,x4,x5,x6,x7x_1, x_2, x_3, x_4, x_5, x_6, x_7. We know x1=4x_1 = 4, median x4=12x_4 = 12, and x7=4+19=23x_7 = 4 + 19 = 23. Since 8 is the unique mode and 8<128 < 12, 8 must fill x2x_2 and x3x_3, giving it a frequency of 2. For 8 to remain the unique mode, no other element can appear more than once. Thus, x5,x6,x7x_5, x_6, x_7 must all be distinct. To maximize the mean, we maximize x5x_5 and x6x_6 under 12<x5<x6<2312 < x_5 < x_6 < 23, yielding x5=21x_5 = 21 and x6=22x_6 = 22. The maximum sum is 4+8+8+12+21+22+23=984 + 8 + 8 + 12 + 21 + 22 + 23 = 98, giving a mean of 98/7=1498 / 7 = 14.

Adım Adım Çözüm

1
Determine the fixed values in the ordered 7-element data set.
Let the 7 integers in non-decreasing order be x1,x2,x3,x4,x5,x6,x7x_1, x_2, x_3, x_4, x_5, x_6, x_7. Given x1=4x_1 = 4, median x4=12x_4 = 12, and range x7x1=19x_7 - x_1 = 19, we find x7=4+19=23x_7 = 4 + 19 = 23.
The median of a 7-element set is the 4th element, and range is maximum minus minimum.
2
Determine the frequency and values of the mode.
Since the unique mode is 88 and 8<128 < 12, the value 88 must occupy positions x2x_2 and x3x_3, so x2=8x_2 = 8 and x3=8x_3 = 8. Thus, 88 appears exactly twice.
Position 1 is 4 and position 4 is 12, leaving only positions 2 and 3 for the mode value of 8.
3
Apply the unique mode constraint to maximize remaining terms.
Because 88 appears twice and is the unique mode, no other number can appear 2 or more times. Hence, all other elements must be distinct. To maximize the sum, we choose the largest distinct integers for x5x_5 and x6x_6 such that 12<x5<x6<2312 < x_5 < x_6 < 23, giving x5=21x_5 = 21 and x6=22x_6 = 22.
Allowing any other value to repeat would create a second mode or a new unique mode, violating the problem conditions.
4
Calculate the maximum sum and arithmetic mean.
The maximal set is {4,8,8,12,21,22,23}\{4, 8, 8, 12, 21, 22, 23\}. The sum is 4+8+8+12+21+22+23=984 + 8 + 8 + 12 + 21 + 22 + 23 = 98. The maximum mean is 98/7=1498 / 7 = 14.
Dividing the maximum possible sum by the total number of elements yields the maximum mean.

Anahtar Kavram

Mean, Median, and Mode Constraints
Soru 1077Soru

Read the summary descriptions of a three-paragraph passage regarding early twentieth-century urban planning. Match each paragraph designation on the left with its primary structural function on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

Paragraph 1: Introduces Ebenezer Howard's 'garden city' model and outlines its core theoretical vision of integrating urban conveniences with rural environments.
Paragraph 2: Details the practical financial and logistical obstacles faced by developers who attempted to build the first garden cities in England.
Paragraph 3: Concludes by evaluating how the garden city movement ultimately shaped modern suburban residential zoning policies.

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Paragraph 1 matches with 'Presents an innovative theoretical framework and its founding principles', Paragraph 2 matches with 'Examines real-world implementation challenges and operational hurdles', and Paragraph 3 matches with 'Assesses the broader, long-term legacy of the concept on contemporary practice'.
Each paragraph maps directly to a distinct stage of the passage's rhetorical progression: introducing a theoretical concept, describing implementation challenges, and assessing long-term legacy.

Adım Adım Çözüm

1
Analyze the primary role of the first paragraph.
The first paragraph introduces Howard's model and its conceptual goals.
This establishes the theoretical foundation of the topic, matching the description of presenting a framework and its principles.
2
Analyze the primary role of the second paragraph.
The second paragraph shifts focus to financial and logistical obstacles in building the cities.
This transitions from theory to real-world application problems, matching the description of implementation challenges.
3
Analyze the primary role of the third paragraph.
The third paragraph looks back at how the movement influenced modern suburban zoning.
This provides a final evaluation of historical impact, matching the description of assessing long-term legacy.

Anahtar Kavram

Determining Paragraph Function and Structural Role
Soru 1078Soru

A boutique clothing retailer purchases a line of jackets for a wholesale price of xx dollars. The retailer marks up the wholesale price by 50%50\% to set the original retail price. During a seasonal clearance sale, the original retail price is discounted by 30%30\%. If a customer purchases a jacket during the clearance sale for $126\$126, what was the original wholesale price of the jacket, xx?

Cevabı ve açıklamayı göster

Cevap: $120\$120

Cevap

The original wholesale price of the jacket is $120\$120.
The wholesale price xx is increased by 50%50\%, giving a retail price of 1.5x1.5x. A 30%30\% discount reduces this retail price to 70%70\% of its value: 1.5x×0.7=1.05x1.5x \times 0.7 = 1.05x. Given that the final price is $126\$126, solving 1.05x=1261.05x = 126 gives x=$120x = \$120.

Adım Adım Çözüm

1
Express the original retail price in terms of the wholesale price xx.
Original Retail Price =x×(1+0.50)=1.50x= x \times (1 + 0.50) = 1.50x
A 50%50\% markup increases the initial value by a factor of 1.501.50.
2
Express the clearance sale price in terms of the original retail price.
Clearance Sale Price =1.50x×(10.30)=1.50x×0.70=1.05x= 1.50x \times (1 - 0.30) = 1.50x \times 0.70 = 1.05x
A 30%30\% discount means paying 70%70\% of the marked-up retail price.
3
Set the sale price expression equal to $126\$126 and solve for xx.
1.05x=126    x=1261.05=12600105=1201.05x = 126 \implies x = \frac{126}{1.05} = \frac{12600}{105} = 120
Dividing the clearance sale price by the net multiplier yields the original wholesale price.

Anahtar Kavram

Successive Percent Change and Multiplier Bases
Soru 1079Soru

A corporate catering service offers two lunch options: a Standard Meal and a Premium Meal. On Monday, an order of 4040 Standard Meals and 2020 Premium Meals cost a total of $1,300\$1,300. On Tuesday, an order of 2020 Standard Meals and 3030 Premium Meals cost a total of $1,250\$1,250. What is the total cost of an order consisting of 1515 Standard Meals and 1515 Premium Meals?

Cevabı ve açıklamayı göster

Cevap: $712.50\$712.50

Cevap

The total cost of 15 Standard Meals and 15 Premium Meals is $712.50.
By setting up the system 40x+20y=130040x + 20y = 1300 and 20x+30y=125020x + 30y = 1250, we simplify to 2x+y=652x + y = 65 and 2x+3y=1252x + 3y = 125. Subtracting the first from the second gives 2y=602y = 60, so y=30y = 30. Substituting y=30y = 30 into 2x+y=652x + y = 65 yields 2x=352x = 35, so x=17.50x = 17.50. The sum of one Standard Meal and one Premium Meal is x+y=47.50x + y = 47.50. Therefore, 1515 of each costs 15×47.50=$712.5015 \times 47.50 = \$712.50. Alternatively, adding the two simplified equations directly yields 4x+4y=190    x+y=47.504x + 4y = 190 \implies x + y = 47.50, so 15(x+y)=15×47.50=$712.5015(x + y) = 15 \times 47.50 = \$712.50.

Adım Adım Çözüm

1
Set up a system of linear equations using variables xx for the price of a Standard Meal and yy for the price of a Premium Meal.
40x+20y=130040x + 20y = 1300 and 20x+30y=125020x + 30y = 1250
Translate the scenario information into algebraic equations.
2
Simplify both equations by dividing by their greatest common factors.
Equation 1: 2x+y=652x + y = 65; Equation 2: 2x+3y=1252x + 3y = 125
Simplifying equations reduces computation complexity.
3
Subtract Equation 1 from Equation 2 to eliminate xx and solve for yy.
(2x+3y)(2x+y)=12565    2y=60    y=30(2x + 3y) - (2x + y) = 125 - 65 \implies 2y = 60 \implies y = 30
Elimination isolates variable yy.
4
Substitute y=30y = 30 back into Equation 1 to solve for xx.
2x+30=65    2x=35    x=17.502x + 30 = 65 \implies 2x = 35 \implies x = 17.50
Finding the value of xx gives the cost of one Standard Meal.
5
Calculate the target linear combination 15x+15y=15(x+y)15x + 15y = 15(x + y).
15(17.50+30.00)=15(47.50)=712.5015(17.50 + 30.00) = 15(47.50) = 712.50
Multiply the combined price of one of each meal by 15.

Anahtar Kavram

Solving systems of two linear equations in two variables using elimination and finding linear combinations.
Tahmini Süre:1m 45s
Soru 1080Soru

For decades, marine ecologists operated under the paradigm that coastal mangrove forests served primarily as passive sediment traps, offering minimal direct nutritional support to offshore coral reef ecosystems. Granted, early isotopic tracing studies confirmed that mangrove-derived organic matter rarely migrated beyond the immediate intertidal zone. Nevertheless, recent micro-chemical analyses of reef fish otoliths have revealed a far more dynamic interdependence: juvenile predatory species depend critically on mangrove estuarine habitats for early-stage foraging before migrating seaward. Still, some researchers maintain that this estuarine dependency is an evolutionary anomaly restricted to specific sub-tropical regions rather than a universal ecological baseline. Ultimately, however, emerging multi-regional data suggest that preserving these estuarine conduits is essential for maintaining global reef biodiversity.

Match each structural pivot or transition phrase from the passage (on the left) to its precise rhetorical function within the author's overall argument trajectory (on the right).

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

"Granted"
"Nevertheless"
"Still"
"Ultimately, however"

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Each transition phrase matches its specific structural role in the argument flow: 'Granted' concedes evidence supporting the traditional model; 'Nevertheless' introduces the primary empirical counter-finding; 'Still' introduces a qualifying objection; and 'Ultimately, however' resolves that objection to establish the author's main takeaway.
The correct pairings trace the passage's rhetorical progression: 'Granted' acknowledges evidence supporting the traditional model, 'Nevertheless' introduces the primary opposing evidence, 'Still' presents a skeptical qualification, and 'Ultimately, however' resolves the debate to state the author's main thesis.

Adım Adım Çözüm

1
Analyze the opening paradigm and the initial concession indicator.
'Granted' admits factual support for the traditional view (isotopic tracing of organic matter) before the passage presents its central argument shift.
Tracking concessive pivots helps distinguish acknowledged background facts from the author's primary argument.
2
Identify the primary adversarial transition that introduces new evidence.
'Nevertheless' marks the main empirical pivot where otolith analysis reveals dynamic interdependence between mangroves and reefs.
Major contrast indicators signal the transition from an outdated hypothesis to the central finding of the passage.
3
Evaluate subsequent qualifications and the final resolving pivot.
'Still' introduces skeptic pushback (the anomaly argument), while 'Ultimately, however' overrides this objection with multi-regional data to state the final purpose.
Multi-stage passages frequently alternate between findings, counter-arguments, and final syntheses.

Anahtar Kavram

Tracking Structural Pivots and Rhetorical Trajectory in Reading Comprehension Passages
ÖncekiSayfa 54 / 110Sonraki
Tüm alıştırma soruları — GMAT | Examkin