Tüm alıştırma soruları

2195 soru

Soru 1001Soru

An agricultural enterprise harvests wheat across three distinct parcels of land: Parcel X, Parcel Y, and Parcel Z. Parcel X covers 120120 acres and yields an average of 4545 bushels per acre. Parcel Y covers 8080 acres and yields an average of 6060 bushels per acre. Parcel Z covers 5050 acres and yields an average of 7070 bushels per acre. What is the overall average yield, in bushels per acre, for the entire enterprise across all three parcels?

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Cevap: 54.854.8

Cevap

The overall average yield for the entire enterprise is 54.854.8 bushels per acre.
To find the overall average yield across all land, compute total production divided by total acreage. Parcel X yields 5,4005,400 bushels (120×45120 \times 45), Parcel Y yields 4,8004,800 bushels (80×6080 \times 60), and Parcel Z yields 3,5003,500 bushels (50×7050 \times 70). Dividing the combined production of 13,70013,700 bushels by the combined area of 250250 acres gives 54.854.8 bushels per acre.

Adım Adım Çözüm

1
Calculate total bushels produced on Parcel X
120 acres×45 bushels/acre=5,400 bushels120 \text{ acres} \times 45 \text{ bushels/acre} = 5,400 \text{ bushels}
Total production for a parcel equals its area multiplied by its yield per acre.
2
Calculate total bushels produced on Parcel Y
80 acres×60 bushels/acre=4,800 bushels80 \text{ acres} \times 60 \text{ bushels/acre} = 4,800 \text{ bushels}
Determine total wheat harvested from Parcel Y.
3
Calculate total bushels produced on Parcel Z
50 acres×70 bushels/acre=3,500 bushels50 \text{ acres} \times 70 \text{ bushels/acre} = 3,500 \text{ bushels}
Determine total wheat harvested from Parcel Z.
4
Sum total bushels and total acreage
Total bushels = 5,400+4,800+3,500=13,700 bushels5,400 + 4,800 + 3,500 = 13,700 \text{ bushels}; Total acres = 120+80+50=250 acres120 + 80 + 50 = 250 \text{ acres}
Weighted average requires total quantity produced divided by total weight (area).
5
Compute the weighted average yield
13,700250=54.8 bushels per acre\frac{13,700}{250} = 54.8 \text{ bushels per acre}
Divide aggregate bushels by aggregate acreage.

Anahtar Kavram

Weighted Averages in Applied Contexts
Tahmini Süre:2m 0s
Soru 1002Soru

An event design company offers three distinct decorative bundles—Bundle X, Bundle Y, and Bundle Z—for corporate gala setups.

• Bundle X contains 3 floral arrangements, 2 LED uplights, and 1 table runner.
• Bundle Y contains 1 floral arrangement, 3 LED uplights, and 2 table runners.
• Bundle Z contains 2 floral arrangements, 1 LED uplight, and 3 table runners.

To decorate a venue, a coordinator orders a combination of these bundles containing a total of 26 floral arrangements, 23 LED uplights, and 23 table runners. If every bundle ordered is used in its entirety, what is the total number of bundles ordered by the coordinator?

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Cevap: 12

Cevap

The total number of bundles ordered by the coordinator is 12.
Summing all three equations gives 6x+6y+6z=726x + 6y + 6z = 72. Factoring out 66 yields 6(x+y+z)=726(x + y + z) = 72, so dividing by 66 gives x+y+z=12x + y + z = 12. Alternatively, solving the system explicitly gives x=5x = 5, y=4y = 4, and z=3z = 3, whose sum is 5+4+3=125 + 4 + 3 = 12.

Adım Adım Çözüm

1
Define variables and set up the system of linear equations based on item counts.
Let xx, yy, and zz represent the number of Bundle X, Bundle Y, and Bundle Z ordered, respectively.
3x+y+2z=26(Floral arrangements)2x+3y+z=23(LED uplights)x+2y+3z=23(Table runners)\begin{aligned} 3x + y + 2z &= 26 \quad \text{(Floral arrangements)} \\ 2x + 3y + z &= 23 \quad \text{(LED uplights)} \\ x + 2y + 3z &= 23 \quad \text{(Table runners)} \end{aligned}
Translate the word problem into a standard system of 3 linear equations in 3 variables.
2
Sum the three equations to find a direct linear combination for (x+y+z)(x + y + z).
(3x+2x+x)+(y+3y+2y)+(2z+z+3z)=26+23+23(3x + 2x + x) + (y + 3y + 2y) + (2z + z + 3z) = 26 + 23 + 23
6x+6y+6z=726x + 6y + 6z = 72
Notice that the sum of coefficients for each variable across all three equations is identical (3+2+1=63 + 2 + 1 = 6).
3
Factor out 6 and solve for the total number of bundles (x+y+z)(x + y + z).
6(x+y+z)=72    x+y+z=126(x + y + z) = 72 \implies x + y + z = 12
Dividing both sides by 6 directly gives the required total quantity without needing to solve for individual variables xx, yy, and zz separately.

Anahtar Kavram

Linear combinations in systems of equations
Tahmini Süre:2m 0s
Soru 1003Soru

A corporate committee needs to form a 5-member project team selected from a department consisting of 4 data analysts, 5 software developers, and 4 cybersecurity experts. The team must include exactly 1 cybersecurity expert, at least 1 data analyst, and at least 1 software developer. How many different 5-member teams can be formed under these conditions?

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Cevap: 480

Cevap

480
To form a valid 5-member team, we first choose 1 cybersecurity expert from 4 available options in (41)=4\binom{4}{1} = 4 ways. The remaining 4 members must be selected from 4 data analysts and 5 software developers such that at least 1 of each role is included. The three mutually exclusive ways to fill these 4 spots are: 1 data analyst and 3 developers (40 ways), 2 data analysts and 2 developers (60 ways), or 3 data analysts and 1 developer (20 ways). Summing these gives 120 valid combinations for the remaining members. Multiplying by the 4 choices for the cybersecurity expert yields 4×120=4804 \times 120 = 480 total distinct teams.

Adım Adım Çözüm

1
Determine the number of ways to select the required cybersecurity expert
4 ways
Selecting exactly 1 cybersecurity expert from a total of 4 available experts is given by the combination (41)=4\binom{4}{1} = 4.
2
Identify the possible valid distributions for the remaining 4 team members
Three valid cases: (1 DA, 3 SD), (2 DA, 2 SD), and (3 DA, 1 SD)
The team requires 5 members in total. With 1 cybersecurity expert selected, 4 positions remain. Since the team must contain at least 1 data analyst (DA) and at least 1 software developer (SD), we list all valid splits of 4 members.
3
Calculate the combinations for each valid distribution of data analysts and software developers
Case 1: 40 ways; Case 2: 60 ways; Case 3: 20 ways
Case 1 (1 DA, 3 SD): (41)×(53)=4×10=40\binom{4}{1} \times \binom{5}{3} = 4 \times 10 = 40.
Case 2 (2 DA, 2 SD): (42)×(52)=6×10=60\binom{4}{2} \times \binom{5}{2} = 6 \times 10 = 60.
Case 3 (3 DA, 1 SD): (43)×(51)=4×5=20\binom{4}{3} \times \binom{5}{1} = 4 \times 5 = 20.
4
Sum the valid remaining member distributions and apply the Fundamental Counting Principle
480 total teams
Total remaining combinations = 40+60+20=12040 + 60 + 20 = 120. Total team combinations = (41)×120=4×120=480\binom{4}{1} \times 120 = 4 \times 120 = 480.

Anahtar Kavram

Group selections with multiple category constraints and the Fundamental Counting Principle
Tahmini Süre:2m 30s
Soru 1004Soru

A motorboat travels 6060 miles downstream in a river with a constant current and then returns upstream along the same route to its starting point. If the motorboat's speed in still water is 2020 miles per hour and the total round-trip journey takes 88 hours, what is the speed of the river current, in miles per hour?

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Cevap: 1010

Cevap

The speed of the river current is 1010 miles per hour.
The correct answer is 1010 miles per hour. Substituting c=10c = 10 into the rates gives a downstream rate of 3030 mph (taking 60/30=260 / 30 = 2 hours) and an upstream rate of 1010 mph (taking 60/10=660 / 10 = 6 hours). The total trip time is 2+6=82 + 6 = 8 hours, which matches the problem description.

Adım Adım Çözüm

1
Define variables and expressions for downstream and upstream rates.
Let cc be the speed of the river current in mph. Downstream rate is 20+c20 + c mph and upstream rate is 20c20 - c mph.
When traveling downstream, the current adds to the boat's still-water speed; when traveling upstream, the current subtracts from it.
2
Set up the total time equation using Time = Distance / Rate.
6020+c+6020c=8\frac{60}{20 + c} + \frac{60}{20 - c} = 8
The sum of the time spent traveling downstream and the time spent traveling upstream equals the total trip duration of 88 hours.
3
Find a common denominator and solve the algebraic equation for cc.
60(20c)+60(20+c)=8(20+c)(20c)    120060c+1200+60c=8(400c2)    2400=32008c260(20 - c) + 60(20 + c) = 8(20 + c)(20 - c) \implies 1200 - 60c + 1200 + 60c = 8(400 - c^2) \implies 2400 = 3200 - 8c^2
Combining the fractions over the common denominator (20+c)(20c)=400c2(20+c)(20-c) = 400 - c^2 allows clear quadratic isolation.
4
Isolate c2c^2 and solve for cc.
8c2=800    c2=100    c=108c^2 = 800 \implies c^2 = 100 \implies c = 10
Since speed must be a positive quantity, c=10c = 10 miles per hour.

Anahtar Kavram

Rate, Time, and Distance Problems in Currents (Upstream and Downstream)
Soru 1005Soru
A software quality team tracked the number of bug tickets resolved daily over a period of 1515 consecutive workdays. The recorded number of resolved tickets for the first 1414 days, listed in ascending order, were: 2,3,3,4,5,5,6,7,8,9,9,10,11,122, 3, 3, 4, 5, 5, 6, 7, 8, 9, 9, 10, 11, 12 If the number of tickets resolved on the 15th15\text{th} day was xx, and the arithmetic mean of the complete 1515-day data set is equal to its median, what is the value of xx?
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Cevap: 1111

Cevap

The value of xx is 1111.
Summing the initial 14 numbers yields 94. In a set of 15 numbers, the median is the 8th term when ordered. Because there are exactly 7 terms smaller than 7 in the initial list, any value of x7x \ge 7 keeps 7 at the 8th position, making the median 7. Setting the mean 94+x15\frac{94+x}{15} equal to 7 gives 94+x=10594 + x = 105, which leads to x=11x = 11.

Adım Adım Çözüm

1
Calculate the sum of the known 14 values.
Sum14=2+3+3+4+5+5+6+7+8+9+9+10+11+12=94\text{Sum}_{14} = 2 + 3 + 3 + 4 + 5 + 5 + 6 + 7 + 8 + 9 + 9 + 10 + 11 + 12 = 94.
The sum of all 15 terms will be 94+x94 + x, making the arithmetic mean 94+x15\frac{94 + x}{15}.
2
Determine the position of the median in a 15-element set.
The median of an odd-numbered set with N=15N = 15 is the 15+12=8th\frac{15+1}{2} = 8\text{th} term when arranged in ascending order.
To set the mean equal to the median, we must determine how xx affects the 8th term.
3
Analyze the position of the 8th term based on potential values of xx.
The first 14 numbers contain 7 values less than 7 (2,3,3,4,5,5,62, 3, 3, 4, 5, 5, 6) and 7 values greater than or equal to 7 (7,8,9,9,10,11,127, 8, 9, 9, 10, 11, 12). Therefore, for any x7x \ge 7, the 8th term in the sorted set of 15 numbers is fixed at 77.
Since 7 values are strictly less than 7, placing x7x \ge 7 ensures that 7 is the 8th smallest value.
4
Set the arithmetic mean equal to the median (77) and solve for xx.
\frac{94 + x}{15} = 7 \implies 94 + x = 105 \implies x = 11.
Since x=117x = 11 \ge 7, the condition holds and the median remains 7.

Anahtar Kavram

Properties of Mean and Median in a Data Set
Soru 1006Soru

Data Set AA consists of nn numbers with mean μ\mu and standard deviation σ\sigma, where σ>0\sigma > 0. Data Set BB is created by transforming each element xx in Data Set AA into y=52xy = 5 - 2x. If the variance of Data Set BB is equal to kk, which of the following expressions represents the standard deviation of Data Set AA in terms of kk?

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Cevap: k2\frac{\sqrt{k}}{2}

Cevap

k2\frac{\sqrt{k}}{2}
Under a linear transformation y=ax+by = ax + b, constant shifts do not change data dispersion, while multiplying elements by aa scales the standard deviation by a|a| and the variance by a2a^2. Here, y=2x+5y = -2x + 5, so a=2a = -2. The variance of Data Set BB is Var(B)=(2)2Var(A)=4σ2\text{Var}(B) = (-2)^2 \cdot \text{Var}(A) = 4\sigma^2. Given Var(B)=k\text{Var}(B) = k, we get 4σ2=k4\sigma^2 = k, which leads to σ2=k4\sigma^2 = \frac{k}{4}. Taking the positive square root yields σ=k2\sigma = \frac{\sqrt{k}}{2}.

Adım Adım Çözüm

1
Analyze the linear transformation rule for standard deviation and variance.
For y=ax+by = ax + b, SD(y)=aSD(x)\text{SD}(y) = |a| \cdot \text{SD}(x) and Var(y)=a2Var(x)\text{Var}(y) = a^2 \cdot \text{Var}(x).
Adding a constant bb shifts all data points equally without altering dispersion, while multiplying by aa scales distance from the mean by a|a|.
2
Apply the transformation y=2x+5y = -2x + 5 to find the variance of Data Set BB in terms of σ\sigma.
\text{Var}(B) = (-2)^2 \cdot \text{Var}(A) = 4\sigma^2.
The coefficient of xx is a=2a = -2, so variance scales by a2=(2)2=4a^2 = (-2)^2 = 4.
3
Set the variance equal to kk and solve for the standard deviation σ\sigma of Data Set AA.
4\sigma^2 = k \implies \sigma^2 = \frac{k}{4} \implies \sigma = \frac{\sqrt{k}}{2}.
Standard deviation is strictly non-negative (σ>0\sigma > 0), requiring the positive square root.

Anahtar Kavram

Linear Transformation of Dispersion Measures
Tahmini Süre:2m 0s
Soru 1007Soru

Set SS consists of nn consecutive integers listed in increasing order. The product of the least integer and the greatest integer in Set SS is equal to 00. If the sum of all the integers in Set SS is 2121, how many integers are in Set SS?

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Cevap: 7

Cevap

7
The given sum of the consecutive integers is positive (2121), which requires the set of consecutive integers to start at 00 rather than end at 00. Setting up the sum formula for consecutive integers from 00 to kk gives k(k+1)2=21\frac{k(k+1)}{2} = 21, solving to k=6k = 6. Including 00, the terms in the set are 0,1,2,3,4,5,60, 1, 2, 3, 4, 5, 6, which yields 60+1=76 - 0 + 1 = 7 integers in total.

Adım Adım Çözüm

1
Analyze the condition for the product of the least and greatest integers.
Since the product of the least integer aa and greatest integer bb is 00, at least one of these extreme terms must be 00.
By the zero-product property, ab=0    a=0a \cdot b = 0 \implies a = 0 or b=0b = 0.
2
Determine which extreme integer is equal to 0.
The least integer aa must be 00.
If b=0b = 0, all integers in the set would be 0\leq 0, so their sum would be 0\leq 0. Since the given sum is 21>021 > 0, the set must consist of non-negative integers starting at 00.
3
Set up the sum equation for consecutive integers starting at 0.
k(k+1)2=21    k(k+1)=42    k=6\frac{k(k+1)}{2} = 21 \implies k(k+1) = 42 \implies k = 6.
The sum of integers from 00 to kk is 0+k(k+1)2=210 + \frac{k(k+1)}{2} = 21.
4
Count the total number of terms in the set.
n=60+1=7n = 6 - 0 + 1 = 7.
The number of integers in an inclusive range from aa to bb is given by ba+1b - a + 1.

Anahtar Kavram

Consecutive Integers, Zero Property, and Inclusive Term Counting
Tahmini Süre:1m 30s
Soru 1008Soru

Let N=24×32×5N = 2^4 \times 3^2 \times 5. How many distinct prime factors does the integer N+9N + 9 have?

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Cevap: 1

Cevap

The integer N+9N + 9 has 1 distinct prime factor.
Evaluating N=24×32×5N = 2^4 \times 3^2 \times 5 gives 720720. Adding 9 yields 729729, which prime factorizes as 363^6. Because 3 is the only unique prime base in this expression, N+9N + 9 has exactly 1 distinct prime factor.

Adım Adım Çözüm

1
Calculate the numerical value of NN from its prime factorization.
N=24×32×5=16×9×5=720N = 2^4 \times 3^2 \times 5 = 16 \times 9 \times 5 = 720
Evaluating NN is necessary to compute N+9N + 9.
2
Add 9 to NN to find the value of N+9N + 9.
N+9=720+9=729N + 9 = 720 + 9 = 729
The question asks for the distinct prime factors of the sum N+9N + 9.
3
Find the prime factorization of 729.
729=36729 = 3^6
Prime factorization reveals the prime bases of the integer.
4
Count the number of distinct prime factors of 729.
The only distinct prime factor is 3, so the count is 1.
Distinct prime factors are the unique prime numbers appearing in the prime factorization.

Anahtar Kavram

Prime Factorization of an Expression Sum
Tahmini Süre:1m 30s
Soru 1009Soru

An electric utility provider generates energy from three distinct sources: Solar, Wind, and Natural Gas. Solar power accounts for 20%20\% of total production at a generation cost of $40\$40 per megawatt-hour (MWh). Wind power accounts for 40%40\% of total production at a generation cost of $30\$30 per MWh. Natural Gas accounts for the remaining production at a generation cost of $80\$80 per MWh. What is the weighted average cost, in dollars per MWh, of the electricity generated by the utility provider?

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Cevap: $52\$52

Cevap

The weighted average cost of electricity is $52\$52 per MWh.
The correct answer reflects the sum of each energy source's unit cost multiplied by its proportion of total output: Solar (0.20×$40=$80.20 \times \$40 = \$8), Wind (0.40×$30=$120.40 \times \$30 = \$12), and Natural Gas (0.40×$80=$320.40 \times \$80 = \$32). Adding these components yields $8+$12+$32=$52\$8 + \$12 + \$32 = \$52 per MWh.

Adım Adım Çözüm

1
Determine the percentage weight of each energy source.
Solar =20%=0.20= 20\% = 0.20, Wind =40%=0.40= 40\% = 0.40, Natural Gas =100%(20%+40%)=40%=0.40= 100\% - (20\% + 40\%) = 40\% = 0.40.
The total proportion of all energy sources must sum to 100%100\% (1.001.00).
2
Calculate the weighted cost contribution for each energy source.
Solar: 0.20×$40=$80.20 \times \$40 = \$8. Wind: 0.40×$30=$120.40 \times \$30 = \$12. Natural Gas: 0.40×$80=$320.40 \times \$80 = \$32.
Multiplying individual unit costs by their corresponding weights yields their contribution to the total average cost per unit.
3
Sum the weighted contributions to find the overall weighted average cost.
Weighted Average Cost =$8+$12+$32=$52= \$8 + \$12 + \$32 = \$52 per MWh.
Adding the individual component contributions yields the overall weighted average.

Anahtar Kavram

Weighted Average Formula: Weighted Average=(wi×xi)\text{Weighted Average} = \sum (w_i \times x_i) where wiw_i represents the relative weight (fraction or percentage) of each component xix_i, and wi=1\sum w_i = 1.
Tahmini Süre:1m 30s
Soru 1010Soru

For decades, evolutionary biologists faced a conceptual paradox regarding the persistence of sexual reproduction despite its substantial genetic costs. Under classical models, an asexual female passes all of her genes to offspring, whereas a sexual female passes only half, theoretically giving asexual lineages a two-fold reproductive advantage that should lead to the rapid competitive exclusion of sexual populations.

To resolve this discrepancy, early theorists posited that sexual reproduction evolved primarily to facilitate the purge of deleterious mutations. However, this mutation-clearing hypothesis failed to explain why sexual populations persist in dynamic ecological environments where mutation rates are exceptionally low.

More recent empirical research on Potamopyrgus antipodarum, a freshwater snail species featuring coexisting sexual and asexual populations, offers a more robust explanation rooted in host-parasite coevolution. Investigators observed that in habitats characterized by high parasite density, sexual individuals significantly outnumber asexual clones. Because parasites rapidly adapt to infect the most common local genotypes, clonal populations suffer severe frequency-dependent mortality over successive generations. Conversely, the novel genetic combinations generated by sexual recombination present a continually moving target for parasitic infection. In parasite-free shallow waters, however, asexual clones quickly dominate the population, confirming the inherent numerical advantage of asexual reproduction when coevolutionary pressures are absent.

Ultimately, these findings demonstrate that ecological interactions can continuously offset the substantial costs of sex. Rather than viewing sexual reproduction as a universal evolutionary ideal or a mere mechanism for mutation repair, evolutionary biologists must recognize that its maintenance depends heavily on localized biotic selection pressures, such as parasite-driven coevolutionary arms races.

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

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Cevap: To present empirical research that offers a resolution to an evolutionary paradox concerning sexual reproduction.

Cevap

The primary purpose of the passage is to present empirical research that offers a resolution to an evolutionary paradox concerning sexual reproduction.
The correct answer accurately summarizes the overall purpose of the passage. The author begins by framing a classical paradox (why sexual reproduction persists despite its two-fold cost), mentions an earlier inadequate theory, introduces recent empirical evidence on freshwater snails, and concludes that host-parasite coevolution provides the key to resolving the paradox.

Adım Adım Çözüm

1
Analyze the structural outline of the passage.
Paragraph 1 introduces the paradox (the two-fold cost of sex). Paragraph 2 notes an incomplete early explanation (mutation clearing). Paragraph 3 presents empirical snail research (host-parasite coevolution). Paragraph 4 summarizes the broader takeaway.
Tracking structural flow helps distinguish the main point from supporting evidence.
2
Synthesize the author's main point and overall objective.
The author aims to explain why sexual reproduction persists despite its heavy theoretical cost, using recent snail research as the key resolving evidence.
The primary purpose must cover the whole text rather than an isolated paragraph or detail.
3
Evaluate option choices against overall scope.
The option stating that the passage presents empirical research offering a resolution to the paradox matches the overall scope perfectly.
Distractors either focus on single details, overstate claims, or misrepresent passage premises.

Anahtar Kavram

Identifying Primary Purpose and Main Idea
Soru 1011Soru

A financial firm has a team of 10 auditors consisting of 6 certified public accountants (CPAs) and 4 audit assistants. A special audit task force of 3 auditors is to be selected at random from the team. If the probability that the task force contains at least one CPA is expressed as a fraction ab\frac{a}{b} in simplest form, what is the value of a+ba + b?

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Cevap: 59

Cevap

59
To find the probability of selecting at least one CPA, it is most efficient to use the complementary probability formula: P(at least 1 CPA)=1P(no CPAs)P(\text{at least 1 CPA}) = 1 - P(\text{no CPAs}). The total number of ways to select any 3 auditors from the team of 10 is given by (103)=10×9×83×2×1=120\binom{10}{3} = \frac{10 \times 9 \times 8}{3 \times 2 \times 1} = 120. The number of ways to select 3 auditors such that none are CPAs (i.e., all 3 are audit assistants) is (43)=4\binom{4}{3} = 4. Therefore, the probability of choosing zero CPAs is 4120=130\frac{4}{120} = \frac{1}{30}. Subtracting from 1 gives 1130=29301 - \frac{1}{30} = \frac{29}{30}. The fraction 2930\frac{29}{30} is in simplest form because 29 is a prime number and does not divide 30. Thus, a=29a = 29 and b=30b = 30, making a+b=59a + b = 59.

Adım Adım Çözüm

1
Calculate total possible combinations for selecting 3 members from 10.
\binom{10}{3} = 120
Selection is made without replacement and order of selection does not matter.
2
Calculate combinations of selecting 3 members with no CPAs.
\binom{4}{3} = 4
All 3 selected members must come from the pool of 4 audit assistants.
3
Determine probability of the complement event (no CPAs).
P(\text{no CPA}) = \frac{4}{120} = \frac{1}{30}
Probability is favorable outcomes over total outcomes.
4
Compute probability of at least one CPA.
P(\text{at least 1 CPA}) = 1 - \frac{1}{30} = \frac{29}{30}
P(\text{at least one}) = 1 - P(\text{none}).
5
Find the sum of numerator a and denominator b in simplest form.
a + b = 29 + 30 = 59
29/30 cannot be simplified further as 29 is a prime number.

Anahtar Kavram

Complementary Probability and At-Least-One Scenarios
Soru 1012Soru

An express delivery drone flies from Station Alpha to Station Beta at a constant speed of 6060 miles per hour against a headwind. On the return flight along the exact same path from Station Beta to Station Alpha, with the wind acting as a tailwind of identical strength, the drone travels at a constant speed of 9090 miles per hour. If the entire round-trip flight took a total of 55 hours, what is the distance, in miles, between Station Alpha and Station Beta?

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Cevap: 180

Cevap

The distance between Station Alpha and Station Beta is 180 miles.
To find the distance DD, set up the total time equation: D60+D90=5\frac{D}{60} + \frac{D}{90} = 5. Finding the common denominator yields 5D180=5\frac{5D}{180} = 5, leading directly to D=180D = 180 miles.

Adım Adım Çözüm

1
Define the unknown variable and write time expressions for each leg.
Let DD be the distance between Station Alpha and Station Beta. Outbound time is D60\frac{D}{60} hours and return time is D90\frac{D}{90} hours.
Using the rate-time-distance formula t=drt = \frac{d}{r} allows expressing unknown time components using distance.
2
Set up an equation for total round-trip time.
D60+D90=5\frac{D}{60} + \frac{D}{90} = 5
The sum of the time spent on the outbound leg and the return leg equals the total given flight time of 55 hours.
3
Solve the algebraic equation for DD.
Finding a common denominator of 180180 gives 3D+2D180=5    5D180=5    5D=900    D=180\frac{3D + 2D}{180} = 5 \implies \frac{5D}{180} = 5 \implies 5D = 900 \implies D = 180.
Multiplying both sides by 180180 clears denominators and isolates DD.

Anahtar Kavram

Rate, Time, and Distance Relationship
Soru 1013Soru

An investor deposits $5,000\$5,000 into Account B, which earns interest at a rate of 20%20\% per year compounded annually for 22 years. The same investor deposits another $5,000\$5,000 into Account A, which earns simple annual interest at a rate of r%r\% per year for 33 years. If the total interest earned from Account B exceeds the total interest earned from Account A by $400\$400, what is the value of rr?

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Cevap: 12

Cevap

The annual simple interest rate r is 12.
To find rr, calculate the interest from each account. Account B grows compounded annually to $5,000×(1.20)2=$7,200\$5,000 \times (1.20)^2 = \$7,200, producing $2,200\$2,200 in interest. Account A produces 5,000×r100×3=150r5,000 \times \frac{r}{100} \times 3 = 150r in simple interest. The problem states that 2,200150r=4002,200 - 150r = 400. Solving for rr gives 150r=1,800150r = 1,800, so r=12r = 12.

Adım Adım Çözüm

1
Calculate the compound interest earned from Account B
Interest from Account B = $2,200
Using the compound interest formula A=P(1+i)nA = P(1 + i)^n, the balance after 2 years is $5,000×(1.20)2=$7,200\$5,000 \times (1.20)^2 = \$7,200. Subtracting the principal gives $7,200$5,000=$2,200\$7,200 - \$5,000 = \$2,200.
2
Express the simple interest earned from Account A in terms of r
Interest from Account A = 150r
Simple interest is calculated as I=P×r100×t=5,000×r100×3=150rI = P \times \frac{r}{100} \times t = 5,000 \times \frac{r}{100} \times 3 = 150r.
3
Formulate and solve the linear equation relating the two interest amounts
r = 12
Subtracting the simple interest from the compound interest gives 2,200150r=4002,200 - 150r = 400. Solving yields 150r=1,800150r = 1,800, which gives r=12r = 12.

Anahtar Kavram

Comparing simple interest and compound interest expressions to solve for an unknown rate
Soru 1014Soru

In a dataset of NN distinct values arranged in ascending order, the pthp\text{th} percentile is defined as the value at position p100×N\left\lceil \frac{p}{100} \times N \right\rceil.

Initially, a dataset contains 100100 distinct test scores. The 40th40\text{th} percentile score is S1S_1 and the 70th70\text{th} percentile score is S2S_2. A researcher adds xx new scores that are strictly less than S1S_1, and yy new scores that are strictly between S1S_1 and S2S_2, where xx and yy are positive integers.

If the 40th40\text{th} percentile score of the expanded dataset remains S1S_1 and the 70th70\text{th} percentile score of the expanded dataset remains S2S_2, what is the maximum possible value of x+yx + y?

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Cevap: 33

Cevap

The maximum possible value of x+yx + y is 33.
The correct choice is 33. By setting up the percentile rank equations using the ceiling function, the position of S1S_1 in the expanded dataset requires 0.4(x+y)=x\lceil 0.4(x + y) \rceil = x, while the position of S2S_2 requires 0.7(x+y)=x+y\lceil 0.7(x + y) \rceil = x + y. Letting k=x+yk = x + y, the ceiling condition 0.7k=k\lceil 0.7k \rceil = k implies k1<0.7kkk - 1 < 0.7k \le k, which simplifies to 0.3k<10.3k < 1 or k<3.33k < 3.33. Since xx and yy are positive integers, kk can take integer values of 22 or 33. Thus, the maximum possible value of x+yx + y is 33.

Adım Adım Çözüm

1
Determine the initial rank positions of S1S_1 and S2S_2 in the 100-element dataset.
Position of S1=0.40×100=40S_1 = \lceil 0.40 \times 100 \rceil = 40; Position of S2=0.70×100=70S_2 = \lceil 0.70 \times 100 \rceil = 70.
Applying the given percentile formula to N=100N = 100 gives the exact index of each score in ascending order.
2
Express the new rank positions of S1S_1 and S2S_2 after inserting xx scores below S1S_1 and yy scores between S1S_1 and S2S_2.
In the new dataset of size 100+x+y100 + x + y, S1S_1 is at position 40+x40 + x and S2S_2 is at position 70+x+y70 + x + y.
Adding xx scores less than S1S_1 shifts S1S_1's rank by xx. Adding yy scores between S1S_1 and S2S_2 further shifts S2S_2's rank by x+yx + y relative to its original position.
3
Formulate the percentile conditions for the expanded dataset of size M=100+x+yM = 100 + x + y.
For S1S_1: 0.40(100+x+y)=40+x    0.4(x+y)=x\lceil 0.40(100 + x + y) \rceil = 40 + x \implies \lceil 0.4(x + y) \rceil = x.
For S2S_2: 0.70(100+x+y)=70+x+y    0.7(x+y)=x+y\lceil 0.70(100 + x + y) \rceil = 70 + x + y \implies \lceil 0.7(x + y) \rceil = x + y.
The percentile rank of S1S_1 must equal its new position 40+x40 + x, and the percentile rank of S2S_2 must equal its new position 70+x+y70 + x + y.
4
Solve for the total added elements k=x+yk = x + y.
From 0.7k=k\lceil 0.7k \rceil = k, we get k1<0.7kkk - 1 < 0.7k \le k, which simplifies to 0.3k<1    k<1033.330.3k < 1 \implies k < \frac{10}{3} \approx 3.33.
By definition of the ceiling function, z=k    k1<zk\lceil z \rceil = k \iff k - 1 < z \le k for integer kk.
5
Evaluate integer solutions for k=x+yk = x + y given x,y1x, y \ge 1.
For k=2k = 2: x=0.4(2)=1x = \lceil 0.4(2) \rceil = 1, y=1y = 1 (valid).
For k=3k = 3: x=0.4(3)=2x = \lceil 0.4(3) \rceil = 2, y=1y = 1 (valid).
The maximum integer value for k=x+yk = x + y is 33.
Since xx and yy are positive integers, k2k \ge 2. The maximum integer k<3.33k < 3.33 is 33.

Anahtar Kavram

Percentile Rank and Indexing with Ceiling Functions
Tahmini Süre:2m 30s
Soru 1015Soru

Set SS consists of consecutive integers. The sum of all positive integers in set SS is 300300, and the median of set SS is 4.5-4.5. How many negative integers are in set SS?

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Cevap: 33

Cevap

The set S contains 33 negative integers.
To find the number of negative integers in set S, first determine the maximum positive integer N in the set using the sum formula for consecutive positive integers: \frac{N(N+1)}{2} = 300, which yields N = 24. Next, use the property that for an evenly spaced set, the median is the average of the smallest and largest numbers: -4.5 = \frac{\text{Smallest} + 24}{2}. Solving for the smallest integer gives -33. Finally, count the negative integers in set S, which run from -33 to -1 inclusive: -1 - (-33) + 1 = 33.

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1
Find the largest integer in Set S
The largest integer is 24.
The positive integers in set S must form a sequence from 1 to N. The sum of positive integers is given by \frac{N(N + 1)}{2} = 300, which simplifies to N(N + 1) = 600. Since 24 \times 25 = 600, N = 24.
2
Find the smallest integer in Set S using the median formula
The smallest integer is -33.
In any set of consecutive integers, the median is equal to the arithmetic mean of the smallest and largest terms: \text{Median} = \frac{\text{Smallest} + \text{Largest}}{2}. Substituting -4.5 for the median and 24 for the largest term gives -4.5 = \frac{\text{Smallest} + 24}{2} \implies \text{Smallest} + 24 = -9 \implies \text{Smallest} = -33.
3
Count the number of negative integers in Set S
There are 33 negative integers.
The negative integers in set S range from -33 to -1, inclusive. The count is calculated as -1 - (-33) + 1 = 33.

Anahtar Kavram

Properties of consecutive integer sets, median-mean equivalence, and inclusive range counting
Tahmini Süre:1m 30s
Soru 1016Soru

Consider the following passage:

For over half a century, classical philologists analyzed the undeciphered Minoan Linear B script under the foundational premise that its underlying language was non-Indo-European, likely related to Etruscan or ancient Anatolian dialects. This consensus persisted largely because scholars assumed that the Mycenaean civilization, which produced the tablets found at Knossos and Pylos, developed in complete linguistic isolation from mainland Greek-speaking populations. Consequently, early decipherment attempts focused almost exclusively on establishing phonetic parallels with Mediterranean language isolates, yielding meager contextual coherence.

However, in 1952, architect and self-taught linguist Michael Ventris introduced a radical structural methodology. Rather than attempting to match isolated symbols to existing non-Indo-European vocabularies, Ventris constructed a complex syllabic grid based strictly on the internal positional frequencies and contextual distributions of signs across thousands of clay fragments. This purely cryptographic approach revealed systemic inflectional patterns characteristic of noun declensions and verb conjugations. When Ventris populated this abstract structural matrix with hypothetical phonetic values derived from early Greek dialects, the texts unexpectedly rendered intelligible Mycenaean Greek—an archaic form of the Greek language predating Homer by several centuries.

Ventris’s breakthrough not only resolved a long-standing epigraphic enigma but also fundamentally transformed Aegean historiography. By demonstrating that Linear B recorded an early Greek dialect, his work compelled historians to revise established chronologies regarding Mycenaean cultural hegemony and its linguistic continuity with classical Hellas. Thus, Ventris proved that rigorous structural analysis of internal script patterns can overturn deeply entrenched historical paradigms.

Statement: The primary purpose of the passage is to explain how a novel methodological approach to deciphering Linear B overturned a longstanding linguistic assumption and reshaped historical understanding of Aegean civilization.

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Cevap: True

Cevap

The statement is True.
The statement accurately expresses the central purpose of the text: summarizing the transition from an incorrect linguistic consensus to a breakthrough structural decipherment that fundamentally altered Aegean historical analysis.

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1
Analyze the structural organization of the passage across all three paragraphs.
Paragraph 1 outlines the traditional view (Linear B as non-Indo-European). Paragraph 2 introduces Ventris's structural grid method and the discovery of Mycenaean Greek. Paragraph 3 details how this breakthrough revised Aegean historical timelines.
To evaluate a primary purpose claim, one must synthesize how individual paragraphs build toward a central communicative goal.
2
Compare the synthesized passage objective with the provided statement.
The statement claims the primary purpose is to explain how a novel methodology overturned an established linguistic assumption and reshaped historical understanding. This matches the full progression from initial premise to method and historical consequence.
A valid primary purpose statement must reflect the main thesis and encompass the full scope of the text without over-focusing on secondary details.
3
Determine the validity of the statement.
Because the statement accurately synthesizes the main idea and scope of the passage, it is True.
The statement avoids common distortion traps such as being overly narrow, overly broad, or misrepresenting the author's stance.

Anahtar Kavram

Identifying Primary Purpose and Main Idea
Soru 1017Soru

A market research study examined the streaming service subscriptions of 250250 households. Every surveyed household subscribes to at least one of three streaming services: Service X, Service Y, or Service Z.

- 130130 households subscribe to Service X.
- 110110 households subscribe to Service Y.
- 120120 households subscribe to Service Z.
- 4040 households subscribe to both Service X and Service Y.
- 3535 households subscribe to both Service Y and Service Z.
- 4545 households subscribe to both Service X and Service Z.

How many households subscribe to all three streaming services?

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Cevap: 10

Cevap

10 households subscribe to all three streaming services.
According to the Principle of Inclusion-Exclusion for three sets, XYZ=X+Y+Z(XY+YZ+XZ)+XYZ|X \cup Y \cup Z| = |X| + |Y| + |Z| - (|X \cap Y| + |Y \cap Z| + |X \cap Z|) + |X \cap Y \cap Z|. Since every household subscribes to at least one service, XYZ=250|X \cup Y \cup Z| = 250. Substituting the values yields 250=130+110+120(40+35+45)+XYZ250 = 130 + 110 + 120 - (40 + 35 + 45) + |X \cap Y \cap Z|, which simplifies to 250=240+XYZ250 = 240 + |X \cap Y \cap Z|. Solving for XYZ|X \cap Y \cap Z| gives 1010.

Adım Adım Çözüm

1
Set up the Inclusion-Exclusion formula for three overlapping sets
Total = |X| + |Y| + |Z| - (|X ∩ Y| + |Y ∩ Z| + |X ∩ Z|) + |X ∩ Y ∩ Z|
Because every household subscribes to at least one service, the total number of households equals the union of all three sets.
2
Sum the individual set sizes and the pairwise intersection sizes
Sum of individual sets = 130 + 110 + 120 = 360; Sum of pairwise intersections = 40 + 35 + 45 = 120
Aggregating individual and overlapping counts simplifies substitution.
3
Substitute the values into the formula and solve for the intersection of all three sets
250 = 360 - 120 + |X ∩ Y ∩ Z| => 250 = 240 + |X ∩ Y ∩ Z| => |X ∩ Y ∩ Z| = 10
Subtracting 240 from 250 yields the exact count of households subscribing to all three services.

Anahtar Kavram

Inclusion-Exclusion Principle for Three Sets
Tahmini Süre:1m 30s
Soru 1018Soru

A commuter drives a total distance of 6060 miles from home to work. Due to heavy morning traffic, the commuter travels the first 3030 miles at a constant speed of 3030 miles per hour. At what constant speed, in miles per hour, must the commuter travel the remaining 3030 miles to achieve an average speed of 4040 miles per hour for the entire 6060-mile trip?

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Cevap: 6060

Cevap

The commuter must travel the remaining 3030 miles at a speed of 6060 miles per hour.
The total trip distance is 6060 miles and the desired overall average speed is 4040 miles per hour, requiring a total time of 1.51.5 hours. Since traveling the first 3030 miles at 3030 miles per hour takes 11 hour, only 0.50.5 hours remain to complete the remaining 3030 miles. Traveling 3030 miles in 0.50.5 hours requires an average speed of 6060 miles per hour.

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1
Calculate the total time required for the entire trip using Total Time=Total DistanceAverage Speed\text{Total Time} = \frac{\text{Total Distance}}{\text{Average Speed}}.
Total Time=60 miles40 mph=1.5 hours\text{Total Time} = \frac{60 \text{ miles}}{40 \text{ mph}} = 1.5 \text{ hours}.
Average speed for a multi-leg trip is defined strictly as total distance divided by total time.
2
Calculate the time spent on the first leg of the trip.
Time for Leg 1=30 miles30 mph=1.0 hour\text{Time for Leg 1} = \frac{30 \text{ miles}}{30 \text{ mph}} = 1.0 \text{ hour}.
Using Time=DistanceSpeed\text{Time} = \frac{\text{Distance}}{\text{Speed}} for the first 3030 miles.
3
Determine the remaining time available for the second leg of the trip.
Time for Leg 2=1.5 hours1.0 hour=0.5 hours\text{Time for Leg 2} = 1.5 \text{ hours} - 1.0 \text{ hour} = 0.5 \text{ hours}.
The sum of the times for both legs must equal the total required trip time.
4
Calculate the required constant speed for the remaining 3030 miles.
Speed for Leg 2=30 miles0.5 hours=60 mph\text{Speed for Leg 2} = \frac{30 \text{ miles}}{0.5 \text{ hours}} = 60 \text{ mph}.
Dividing the remaining distance by the remaining time gives the required speed for the second leg.

Anahtar Kavram

Average Speed Formula (Vavg=Total DistanceTotal TimeV_{\text{avg}} = \frac{\text{Total Distance}}{\text{Total Time}})
Tahmini Süre:2m 0s
Soru 1019Soru

A furniture manufacturer allows customers to customize a dining set by selecting options from four categories:
- Tabletop shape: rectangular, oval, or round (3 choices)
- Wood finish: oak, walnut, cherry, or maple (4 choices)
- Leg design: tapered, hairpin, or turned (3 choices)
- Number of chairs: 4, 6, or 8 (3 choices)

However, due to space constraints, a round tabletop cannot be paired with a set of 8 chairs. How many distinct dining set configurations can a customer assemble?

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Cevap: 96

Cevap

96 distinct dining set configurations can be assembled.
To find the number of valid dining set configurations, calculate total unrestricted choices using the Fundamental Counting Principle: multiplying 3 tabletop shapes, 4 wood finishes, 3 leg designs, and 3 chair count options gives 108 total combinations. Next, count the prohibited combinations consisting of a round tabletop (1 option) paired with 8 chairs (1 option) across all 4 finishes and 3 leg designs, giving 1 × 4 × 3 × 1 = 12 restricted combinations. Subtracting 12 restricted combinations from 108 total combinations yields 96 valid configurations.

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1
Calculate total possible combinations without restrictions
3 × 4 × 3 × 3 = 108 combinations
By the Fundamental Counting Principle, multiplying the number of available options across all independent decision stages gives the total number of unrestricted arrangements.
2
Calculate the number of invalid configurations violating the space constraint
1 × 4 × 3 × 1 = 12 invalid combinations
Restricted configurations consist of 1 tabletop shape (round), 4 wood finishes, 3 leg designs, and 1 chair quantity selection (8 chairs).
3
Subtract the invalid combinations from the total unrestricted combinations
108 - 12 = 96 valid configurations
Subtracting the prohibited configurations from the total possible combinations yields the count of permissible configurations.

Anahtar Kavram

Fundamental Counting Principle with Subtraction of Restricted Cases
Soru 1020Soru

For decades, planetary scientists attributed the unusual seismic activity observed on Mars's northern plains entirely to deep-seated mantle plumes pushing upward against the planet's crust. This mantle-plume model offered a tidy explanation for the localized surface deformation and volcanic features found in regions such as Elysium Planitia. However, recent high-resolution gravitational data and satellite radar mapping have challenged this long-standing consensus. The new measurements reveal that the subterranean mass anomalies beneath these plains are laterally extensive yet vertically shallow—a structural signature inconsistent with the deep, narrow conduits characteristic of mantle plumes.

To account for these findings, a rival group of geophysicists has proposed an alternative mechanism: lithospheric flexure driven by ancient subcrustal magmatic intrusions. According to this model, magmatic bodies cooled and solidified within the lower crust billions of years ago, creating dense subterranean loads that continue to exert mechanical stress on the surrounding rock today. While proponents of the mantle-plume theory contend that current heat-flow models cannot easily support such persistent localized stress without ongoing thermal upwelling, the magmatic-intrusion hypothesis better accommodates the shallow depth and geometry of the observed gravitational signatures. Ultimately, while neither model has decisively disproved the other, the debate highlights how shifting technological capabilities force researchers to reevaluate foundational planetary geodynamics models rather than treating early orbital inferences as definitive.

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

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Cevap: evaluate two competing geophysical models explaining Martian seismic and gravitational anomalies in light of recent empirical evidence

Cevap

The primary purpose of the passage is to evaluate two competing geophysical models explaining Martian seismic and gravitational anomalies in light of recent empirical evidence.
The correct option accurately synthesizes the full scope of the text. The passage introduces a traditional theory (mantle-plume model), presents new data contradicting it, outlines a rival explanation (magmatic-intrusion hypothesis), compares their strengths and weaknesses, and concludes with a nuanced summary of the scientific debate.

Adım Adım Çözüm

1
Analyze the passage structure and paragraph roles
Paragraph 1 introduces the traditional mantle-plume model and presents new radar/gravitational data that challenge it. Paragraph 2 introduces the alternative magmatic-intrusion model, contrasts the two theories, and concludes with a broader synthesis on scientific reevaluation.
Tracking structural transitions allows identification of the overall narrative arc rather than isolated facts.
2
Determine the author's main objective across all paragraphs
The author presents both the traditional and rival hypotheses, compares how well each accounts for recent data, and maintains a balanced stance noting that neither model is fully proven.
The primary purpose must cover the complete scope of the text without being overly narrow or unjustifiably extreme.
3
Evaluate option choices against the passage scope
The option describing the evaluation of two competing geophysical models accurately reflects the passage's main idea and balanced perspective.
Eliminating options that focus on minor details, extreme claims, or misattributed perspectives yields the correct primary purpose.

Anahtar Kavram

Identifying Primary Purpose in Multi-Viewpoint Reading Comprehension Passages
Tahmini Süre:2m 30s
ÖncekiSayfa 51 / 110Sonraki
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