Tüm alıştırma soruları

231 soru

Soru 141Soru

A bookshelf holds 44 distinct fiction novels and 33 distinct non-fiction books. If a reader chooses exactly 11 fiction novel and 11 non-fiction book to take on a trip, how many different pairs of books can the reader select?

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Cevap: 12

Cevap

The total number of different pairs of books that can be selected is 1212.
According to the Fundamental Counting Principle, if one task can be performed in mm ways and a second task can be performed in nn ways, the two tasks together can be performed in m×nm \times n ways. Choosing a fiction novel (44 options) and a non-fiction book (33 options) results in 4×3=124 \times 3 = 12 unique pairs.

Adım Adım Çözüm

1
Determine the number of ways to choose one fiction novel
There are 44 possible choices.
The shelf contains 44 distinct fiction novels.
2
Determine the number of ways to choose one non-fiction book
There are 33 possible choices.
The shelf contains 33 distinct non-fiction books.
3
Calculate total pairs using the Fundamental Counting Principle
4×3=124 \times 3 = 12
The selection of a fiction novel and a non-fiction book are independent decisions, so the number of outcomes is the product of the number of choices for each decision.

Anahtar Kavram

Fundamental Counting Principle
Soru 142Soru

In the xyxy-plane, line kk has a slope of 34\frac{3}{4} and passes through the point (2,1)(2, 1). Line kk intersects the line x=10x = 10 at point PP. What is the distance between point PP and the point (2,1)(2, 1)?

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Cevap: 10

Cevap

10
Point P lies on the line x = 10, so its x-coordinate is 10. The horizontal change from x = 2 to x = 10 is 8 units. Given that line k has slope 3/4, the corresponding vertical change is (3/4)(8) = 6 units. Therefore, point P has coordinates (10, 7). The distance between (2, 1) and (10, 7) is sqrt((10 - 2)^2 + (7 - 1)^2) = sqrt(64 + 36) = sqrt(100) = 10.

Adım Adım Çözüm

1
Determine the coordinates of point P
P is located at (10, 7)
Since P lies on the line x = 10, its x-coordinate is 10. The horizontal distance from (2, 1) to P is 10 - 2 = 8. Using the slope m = 3/4, the vertical change is (3/4) * 8 = 6, so the y-coordinate of P is 1 + 6 = 7.
2
Calculate the distance between (2, 1) and (10, 7)
The distance is 10
Using the distance formula sqrt((10 - 2)^2 + (7 - 1)^2) = sqrt(8^2 + 6^2) = sqrt(64 + 36) = sqrt(100) = 10.

Anahtar Kavram

Slope definition and distance formula in coordinate geometry
Tahmini Süre:1m 30s
Soru 143Soru

For all real numbers xx, the function gg is defined by g(x)=cx+5g(x) = cx + 5, where cc is a constant. The custom operation \diamond is defined for all real numbers aa and bb by ab=g(a+b)g(ab)a \diamond b = g(a+b) - g(a-b). If 31=123 \diamond 1 = 12, what is the value of g(4)g(4)?

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Cevap: 29

Cevap

29
Applying the function definition g(x)=cx+5g(x) = cx + 5 to the custom operation yields ab=[c(a+b)+5][c(ab)+5]=2bca \diamond b = [c(a+b)+5] - [c(a-b)+5] = 2bc. Substituting a=3a=3 and b=1b=1 into 31=123 \diamond 1 = 12 gives 2(1)c=122(1)c = 12, so c=6c = 6. Consequently, g(x)=6x+5g(x) = 6x + 5, and evaluating at x=4x = 4 yields g(4)=6(4)+5=29g(4) = 6(4) + 5 = 29.

Adım Adım Çözüm

1
Substitute (a+b)(a+b) and (ab)(a-b) into the function definition g(x)=cx+5g(x) = cx + 5 to simplify aba \diamond b.
ab=[c(a+b)+5][c(ab)+5]=2bca \diamond b = [c(a+b) + 5] - [c(a-b) + 5] = 2bc.
Applying the definition of the custom binary operation in terms of function gg eliminates the constant term 55.
2
Use the given equality 31=123 \diamond 1 = 12 to determine the constant cc.
2(1)c=12    2c=12    c=62(1)c = 12 \implies 2c = 12 \implies c = 6.
Plugging a=3a=3 and b=1b=1 into 2bc=122bc = 12 yields an equation in terms of cc.
3
Evaluate g(4)g(4) using c=6c = 6.
g(4)=6(4)+5=29g(4) = 6(4) + 5 = 29.
Substituting x=4x = 4 into g(x)=6x+5g(x) = 6x + 5 calculates the required numerical value.

Anahtar Kavram

Functions and Custom Symbol Operations
Tahmini Süre:1m 30s
Soru 144Soru

In the xyxy-plane, line mm has an xx-intercept of 6-6 and a yy-intercept of 33. Line kk is perpendicular to line mm and passes through the point (4,9)(4, 9). What is the xx-intercept of line kk?

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Cevap: 8.5

Cevap

8.5
First, determine the slope of line mm using the given intercepts (6,0)(-6,0) and (0,3)(0,3), yielding 300(6)=12\frac{3-0}{0-(-6)} = \frac{1}{2}. Since line kk is perpendicular to line mm, its slope is the negative reciprocal of 12\frac{1}{2}, which is 2-2. Using the point-slope equation with point (4,9)(4,9), the equation of line kk is y9=2(x4)y - 9 = -2(x - 4), simplifying to y=2x+17y = -2x + 17. Finding the xx-intercept by setting y=0y = 0 yields 0=2x+170 = -2x + 17, giving x=8.5x = 8.5.

Adım Adım Çözüm

1
Calculate the slope of line mm
Slope of line mm is 12\frac{1}{2}
Line mm passes through the points (6,0)(-6,0) and (0,3)(0,3).
2
Determine the slope of perpendicular line kk
Slope of line kk is 2-2
Perpendicular lines have negative reciprocal slopes.
3
Derive the equation of line kk
y=2x+17y = -2x + 17
Use point-slope form with given point (4,9)(4,9) and slope 2-2.
4
Solve for the xx-intercept of line kk
x=8.5x = 8.5
Set y=0y = 0 in the linear equation y=2x+17y = -2x + 17.

Anahtar Kavram

Perpendicular lines, slope calculation from intercepts, and line equations
Soru 145Soru

A commercial bakery uses two automated ovens, Oven X and Oven Y, to bake identical orders of bread. Working alone at its constant rate, Oven X bakes a full order of bread in 88 hours, while Oven Y, working alone at its constant rate, bakes the same order in 1212 hours. Both ovens begin baking a full order together at 8:00 a.m. At 10:00 a.m., Oven X shuts down due to a maintenance alert, and Oven Y continues working alone at its constant rate until the order is completed. How many total hours, from 8:00 a.m. until completion, does it take to finish the order?

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Cevap: 9

Cevap

The total time required from 8:00 a.m. to complete the order is 99 hours.
Working together for 22 hours at a combined rate of 18+112=524\frac{1}{8} + \frac{1}{12} = \frac{5}{24} per hour completes 512\frac{5}{12} of the order. The remaining 712\frac{7}{12} of the order takes Oven Y 77 hours to complete at its rate of 112\frac{1}{12} per hour. Adding the initial 22 hours gives a total time of 99 hours.

Adım Adım Çözüm

1
Determine the individual hourly work rates.
Oven X completes 18\frac{1}{8} of the job per hour, and Oven Y completes 112\frac{1}{12} of the job per hour.
Work rate is the reciprocal of the total time required to complete one full job.
2
Calculate the fraction of the job completed in the first 22 hours.
Combined rate is 18+112=524\frac{1}{8} + \frac{1}{12} = \frac{5}{24} job per hour. In 22 hours, they complete 2×524=5122 \times \frac{5}{24} = \frac{5}{12} of the job.
Both ovens work simultaneously for 22 hours before Oven X stops.
3
Determine the remaining fraction of the job.
1512=7121 - \frac{5}{12} = \frac{7}{12} of the job remains.
The full order represents 11 whole unit of work.
4
Find the additional time required for Oven Y to finish the remaining job alone.
Time=7/121/12=7\text{Time} = \frac{7/12}{1/12} = 7 hours.
Time equals remaining work divided by Oven Y's individual work rate.
5
Calculate the total time elapsed from start to completion.
2+7=92 + 7 = 9 hours.
The total time includes the 22 hours of combined work plus the 77 hours Oven Y worked alone.

Anahtar Kavram

Combined Work Rates and Modeling Staggered Work
Soru 146Soru

In the xyxy-coordinate plane, point AA has coordinates (9,0)(-9, 0) and point CC has coordinates (0,12)(0, 12). Point BB lies on the positive xx-axis such that line segment BDBD is perpendicular to segment ACAC, with point DD lying on segment ACAC. If the area of right triangle ABDABD is 5454, what is the length of segment OBOB, where OO is the origin (0,0)(0,0)?

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Cevap: 6

Cevap

The length of segment OBOB is 66.
The length of segment OBOB is 66. Using the Pythagorean theorem on AOC\triangle AOC, hypotenuse AC=15AC = 15, establishing a 3:4:53:4:5 side ratio for AOC\triangle AOC. Because ABD\triangle ABD shares acute angle A\angle A with AOC\triangle AOC and has a right angle at DD, ABD\triangle ABD is also a 3:4:53:4:5 right triangle with hypotenuse ABAB. Expressing the area 12×(35AB)×(45AB)=54\frac{1}{2} \times \left(\frac{3}{5}AB\right) \times \left(\frac{4}{5}AB\right) = 54 yields AB=15AB = 15. Since AA is at (9,0)(-9,0), point BB is at (6,0)(6,0), making OB=6OB = 6.

Adım Adım Çözüm

1
Find the side lengths and hypotenuse of right triangle AOCAOC.
Leg AO=9AO = 9, leg OC=12OC = 12, and by the Pythagorean theorem, hypotenuse AC=92+122=81+144=225=15AC = \sqrt{9^2 + 12^2} = \sqrt{81 + 144} = \sqrt{225} = 15.
The coordinates of A(9,0)A(-9,0) and C(0,12)C(0,12) form a right triangle at the origin O(0,0)O(0,0).
2
Use angle similarity to determine the side ratio of right triangle ABDABD.
Triangle ABDABD is similar to triangle AOCAOC because both contain a right angle and share DAO\angle DAO. Thus, the sides of ABD\triangle ABD maintain the ratio AD:BD:AB=3:4:5AD : BD : AB = 3 : 4 : 5.
Right triangles with a shared acute angle are similar.
3
Express legs ADAD and BDBD in terms of hypotenuse ABAB and set up the area equation.
AD=35ABAD = \frac{3}{5}AB and BD=45ABBD = \frac{4}{5}AB. The area of ABD=12×AD×BD=12×35AB×45AB=625AB2\triangle ABD = \frac{1}{2} \times AD \times BD = \frac{1}{2} \times \frac{3}{5}AB \times \frac{4}{5}AB = \frac{6}{25}AB^2. Setting 625AB2=54\frac{6}{25}AB^2 = 54 yields AB2=225AB^2 = 225, so AB=15AB = 15.
The area of a right triangle is half the product of its perpendicular legs.
4
Calculate the length of segment OBOB.
Since point AA is at (9,0)(-9,0) and BB lies on the positive xx-axis, AB=xB(9)=15    xB=6AB = x_B - (-9) = 15 \implies x_B = 6. Therefore, the length of OBOB is 66.
The distance from the origin (0,0)(0,0) to (6,0)(6,0) on the xx-axis is equal to the xx-coordinate 66.

Anahtar Kavram

Applying Pythagorean triples (3-4-5 right triangle family) and similar right triangles in coordinate geometry.
Soru 147Soru

A reliability study recorded the operating lifespan, tt (in thousands of hours), for a sample of 250250 semiconductor laser diodes. The results are summarized in the grouped frequency table below.

Lifespan tt (thousands of hours)Frequency
0t<40 \le t < 43535
4t<84 \le t < 85555
8t<128 \le t < 128080
12t<1612 \le t < 165050
16t<2016 \le t < 203030

Laser diodes with an operating lifespan of at least 60006{}000 hours (t6t \ge 6) but less than 1400014{}000 hours (t<14t < 14) are designated as high-efficiency units. Assuming that the values within each class interval are uniformly distributed, what percentage of the 250250 laser diodes in the sample are designated as high-efficiency units?

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Cevap: 53

Cevap

53%
To find the percentage of diodes with lifespans between 60006{}000 and 1400014{}000 hours (6t<146 \le t < 14), evaluate the relevant intervals. For 4t<84 \le t < 8, the sub-interval [6,8)[6, 8) represents 8684=0.5\frac{8-6}{8-4} = 0.5 of the interval width, containing 0.5×55=27.50.5 \times 55 = 27.5 diodes. The interval [8,12)[8, 12) is fully contained, contributing 8080 diodes. For 12t<1612 \le t < 16, the sub-interval [12,14)[12, 14) represents 14121612=0.5\frac{14-12}{16-12} = 0.5 of the interval width, containing 0.5×50=250.5 \times 50 = 25 diodes. Totaling these gives 27.5+80+25=132.527.5 + 80 + 25 = 132.5 diodes. Expressed as a percentage of the total 250250 diodes, 132.5250×100%=53%\frac{132.5}{250} \times 100\% = 53\%.

Adım Adım Çözüm

1
Determine the estimated number of diodes in the partial interval 6t<86 \le t < 8.
The target range [6,8)[6, 8) covers half of the interval [4,8)[4, 8) width of 44 units. With uniform distribution, the count is 0.5×55=27.50.5 \times 55 = 27.5 diodes.
Linear interpolation estimates frequencies for sub-intervals within grouped data.
2
Include the count for the complete interval 8t<128 \le t < 12.
All 8080 diodes in this interval fall within 6t<146 \le t < 14.
The entire interval is fully contained within the target upper and lower bounds.
3
Determine the estimated number of diodes in the partial interval 12t<1412 \le t < 14.
The target range [12,14)[12, 14) covers half of the interval [12,16)[12, 16) width of 44 units. With uniform distribution, the count is 0.5×50=250.5 \times 50 = 25 diodes.
Linear interpolation estimates frequencies for the upper partial boundary.
4
Sum the target diode counts and convert to a percentage of the total sample.
Total target count = 27.5+80+25=132.527.5 + 80 + 25 = 132.5 diodes. Percentage = 132.5250×100%=53%\frac{132.5}{250} \times 100\% = 53\%.
Divide the calculated frequency sum by the total sample size of 250 and multiply by 100.

Anahtar Kavram

Grouped Frequency Distribution and Linear Interpolation
Tahmini Süre:2m 0s
Soru 148Soru

A community health center conducted a study of 250250 adults regarding their participation in three wellness programs: Nutrition Counseling (NN), Exercise Coaching (EE), and Stress Management (SS). The survey revealed the following data:

125125 adults participate in Nutrition Counseling.
105105 adults participate in Exercise Coaching.
8585 adults participate in Stress Management.
1515 adults participate in all three programs.
3030 adults participate in none of the three programs.

How many adults participate in exactly two of the three programs?

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Cevap: 65

Cevap

65
The total number of surveyed adults is 250250, and 3030 participate in none of the programs, meaning 220220 adults participate in at least one program. Let x1x_1 be the number of adults in exactly one program, x2x_2 in exactly two programs, and x3=15x_3 = 15 in all three programs. We have x1+x2+15=220x_1 + x_2 + 15 = 220, which simplifies to x1+x2=205x_1 + x_2 = 205. Additionally, summing the individual program participants yields N+E+S=125+105+85=315|N| + |E| + |S| = 125 + 105 + 85 = 315. By region expansion, N+E+S=x1+2x2+3x3|N| + |E| + |S| = x_1 + 2x_2 + 3x_3. Substituting x3=15x_3 = 15 gives x1+2x2+45=315x_1 + 2x_2 + 45 = 315, or x1+2x2=270x_1 + 2x_2 = 270. Subtracting x1+x2=205x_1 + x_2 = 205 from x1+2x2=270x_1 + 2x_2 = 270 gives x2=65x_2 = 65.

Adım Adım Çözüm

1
Determine the number of adults in the union of all three set categories
NES=25030=220|N \cup E \cup S| = 250 - 30 = 220
Subtracting the individuals participating in none of the programs from the total surveyed yields the total count of individuals participating in at least one program.
2
Set up an equation for the total unique participants using disjoint region variables
x1+x2=205x_1 + x_2 = 205
The union equals x1+x2+x3=220x_1 + x_2 + x_3 = 220, where x1x_1 represents adults in exactly 1 program, x2x_2 in exactly 2, and x3=15x_3 = 15 in all 3 programs.
3
Set up an equation using the sum of the individual program totals
x1+2x2=270x_1 + 2x_2 = 270
The sum N+E+S=125+105+85=315|N| + |E| + |S| = 125 + 105 + 85 = 315 counts single-program participants once, double-program participants twice, and triple-program participants three times (x1+2x2+3(15)=315x_1 + 2x_2 + 3(15) = 315).
4
Solve the system of linear equations for x2x_2
x2=270205=65x_2 = 270 - 205 = 65
Subtracting (x1+x2=205)(x_1 + x_2 = 205) from (x1+2x2=270)(x_1 + 2x_2 = 270) isolates x2x_2, which is the exact number of adults participating in exactly two programs.

Anahtar Kavram

3-Set Inclusion-Exclusion Principle & Venn Diagram Region Partitioning
Tahmini Süre:1m 45s
Soru 149Soru

A committee of 88 people consists of 44 men and 44 women. A subcommittee of 44 people is to be selected from this group such that the subcommittee contains at least one man and at least one woman. If two specific members, one man and one woman, refuse to serve together on the same subcommittee, how many different valid subcommittees of 44 people can be formed?

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Cevap: 53

Cevap

53
The total number of ways to choose 4 people out of 8 is (84)=70\binom{8}{4} = 70. Removing the 2 single-gender subcommittees (4 men or 4 women) leaves 68 gender-valid subcommittees. Among these 68 subcommittees, exactly (62)=15\binom{6}{2} = 15 contain both of the two conflicting individuals. Subtracting these 15 forbidden subcommittees gives 6815=5368 - 15 = 53 valid subcommittees.

Adım Adım Çözüm

1
Calculate total ways to pick 4 people out of 8 without restrictions
\binom{8}{4} = \frac{8 \times 7 \times 6 \times 5}{4 \times 3 \times 2 \times 1} = 70
This establishes the total baseline sample space of possible 4-person groups.
2
Exclude single-gender groups to satisfy the gender balance constraint
70 - \binom{4}{4} - \binom{4}{4} = 70 - 1 - 1 = 68
Groups with 0 men or 0 women are invalid.
3
Count the forbidden groups that contain both of the conflicting individuals
\binom{6}{2} = 15
Fixing the 2 specific individuals in the subcommittee requires selecting 2 additional members from the remaining 6 people.
4
Subtract forbidden groups from gender-valid groups
68 - 15 = 53
Every group containing both conflicting individuals already satisfies the gender constraint, so exactly 15 invalid groups must be removed from the 68 gender-valid groups.

Anahtar Kavram

Combinations with multiple overlapping constraints (complementary counting)
Soru 150Soru

A machine operates using two independent components, Component AA and Component BB. The probability that Component AA functions properly on a given day is 0.900.90, and the probability that Component BB functions properly on that same day is 0.800.80. What is the probability that at least one of the components functions properly on a given day?

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Cevap: 0.98

Cevap

The probability that at least one component functions properly is 0.980.98.
To determine the probability that at least one component functions properly, use the complement rule: P(at least one)=1P(neither)P(\text{at least one}) = 1 - P(\text{neither}). Since Component AA and Component BB operate independently, the probability that AA fails is 10.90=0.101 - 0.90 = 0.10 and the probability that BB fails is 10.80=0.201 - 0.80 = 0.20. The probability of both components failing simultaneously is 0.10×0.20=0.020.10 \times 0.20 = 0.02. Subtracting this probability from 11 gives 10.02=0.981 - 0.02 = 0.98.

Adım Adım Çözüm

1
Find the probability of failure for each component.
P(Ac)=10.90=0.10P(A^c) = 1 - 0.90 = 0.10 and P(Bc)=10.80=0.20P(B^c) = 1 - 0.80 = 0.20
The event that a component fails is the complement of the event that it functions properly.
2
Calculate the joint probability of both components failing.
P(Ac and Bc)=0.10×0.20=0.02P(A^c \text{ and } B^c) = 0.10 \times 0.20 = 0.02
Because the components operate independently, their failure events are independent, so their individual probabilities are multiplied.
3
Calculate the probability that at least one component functions properly.
P(at least one functions)=10.02=0.98P(\text{at least one functions}) = 1 - 0.02 = 0.98
The event 'at least one component functions' is the exact complement of 'both components fail'.

Anahtar Kavram

Probability of Independent Events and Complement Rule
Tahmini Süre:45s
Soru 151Soru

A commercial print shop uses two high-speed printing presses, Press Alpha and Press Beta. Press Alpha operates at a constant rate of 120120 pages per minute, while Press Beta operates at a constant rate of 180180 pages per minute. Press Alpha begins printing a job of 15,00015,000 pages at 9:00 AM. At 9:15 AM, Press Beta is turned on to assist Press Alpha, and both presses continue printing simultaneously at their respective constant rates until the job is completed. How many total minutes after 9:00 AM will the entire 15,00015,000-page job be finished?

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Cevap: 59

Cevap

The entire 15,000-page job will be finished 59 minutes after 9:00 AM.
Press Alpha operates alone for the first 15 minutes, completing 15×120=1,80015 \times 120 = 1,800 pages. That leaves 15,0001,800=13,20015,000 - 1,800 = 13,200 pages. Once Press Beta joins at 9:15 AM, the combined rate becomes 120+180=300120 + 180 = 300 pages per minute. The remaining pages require 13,200/300=4413,200 / 300 = 44 minutes. Summing the 15-minute initial period and the 44-minute joint period gives a total of 59 minutes after 9:00 AM.

Adım Adım Çözüm

1
Find the work completed by Press Alpha during the 15-minute staggered start period.
1,800 pages completed.
Press Alpha ran alone for 15 minutes at 120 pages per minute.
2
Determine the remaining work to be done after 9:15 AM.
13,200 pages remaining.
Subtract the completed pages from the total batch size of 15,000 pages.
3
Calculate the combined work rate of Press Alpha and Press Beta.
300 pages per minute.
When working together, rates add linearly: 120 + 180 = 300.
4
Calculate time needed to complete the remaining pages.
44 minutes.
Divide remaining work (13,200 pages) by combined rate (300 pages/min).
5
Calculate total elapsed time from 9:00 AM.
59 minutes.
Combine the 15 initial minutes with the 44 subsequent minutes.

Anahtar Kavram

Linear work-rate equations with staggered initial start times
Tahmini Süre:1m 30s
Soru 152Soru

For all non-zero real numbers aa and bb, the custom binary operation \diamondsuit is defined by ab=a2b2aba \diamondsuit b = \frac{a^2 - b^2}{ab}. If the function ff is defined for all x0x \neq 0 by f(x)=x2f(x) = x \diamondsuit 2, what is the value of f(4)f(1)f(4) - f(1)?

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Cevap: 3

Cevap

3
Evaluating f(4)=42=1648=1.5f(4) = 4 \diamondsuit 2 = \frac{16 - 4}{8} = 1.5 and f(1)=12=142=1.5f(1) = 1 \diamondsuit 2 = \frac{1 - 4}{2} = -1.5, the required difference is f(4)f(1)=1.5(1.5)=3f(4) - f(1) = 1.5 - (-1.5) = 3.

Adım Adım Çözüm

1
Evaluate f(4)f(4) using the custom operation definition
f(4)=422242=128=1.5f(4) = \frac{4^2 - 2^2}{4 \cdot 2} = \frac{12}{8} = 1.5
Substitute a=4a = 4 and b=2b = 2 into ab=a2b2aba \diamondsuit b = \frac{a^2 - b^2}{ab}.
2
Evaluate f(1)f(1) using the custom operation definition
f(1)=122212=1.5f(1) = \frac{1^2 - 2^2}{1 \cdot 2} = -1.5
Substitute a=1a = 1 and b=2b = 2 into ab=a2b2aba \diamondsuit b = \frac{a^2 - b^2}{ab}.
3
Compute the difference f(4)f(1)f(4) - f(1)
3
Subtracting 1.5-1.5 from 1.51.5 yields 1.5(1.5)=1.5+1.5=31.5 - (-1.5) = 1.5 + 1.5 = 3.

Anahtar Kavram

Custom Symbol Operations and Function Evaluation
Tahmini Süre:1m 30s
Soru 153Soru

A research committee must select a delegation of 66 members from a pool of 44 senior fellows and 44 junior analysts to sit around a circular conference table with 66 evenly spaced seats. The delegation must consist of exactly 33 senior fellows and 33 junior analysts. If no two senior fellows may sit in adjacent seats around the table, how many distinct delegation seating arrangements are possible? (Two seating arrangements are considered identical if one can be rotated to match the other.)

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Cevap: 192

Cevap

The total number of distinct delegation seating arrangements is 192.
To find the total number of distinct delegation seating arrangements, we first determine how many ways the 6 delegates can be selected, and then multiply by the number of valid circular seating arrangements for those delegates.

1. Selection of Delegates:
- Ways to select 3 senior fellows from 4: (43)=4\binom{4}{3} = 4
- Ways to select 3 junior analysts from 4: (43)=4\binom{4}{3} = 4
- Total delegate combinations: 4×4=164 \times 4 = 16

2. Circular Seating Arrangements:
- With 3 seniors and 3 juniors at a 6-seat table, no two seniors can sit adjacent if and only if seniors and juniors alternate seats.
- Fix one senior fellow to eliminate rotational symmetry.
- The remaining 2 seniors can be arranged in 2!=22! = 2 ways.
- The 3 junior analysts can be arranged in the 3 intermediate seats in 3!=63! = 6 ways.
- Seating arrangements per delegation = 2×6=122 \times 6 = 12

3. Total Arrangements:
- Total = 16×12=19216 \times 12 = 192.

Adım Adım Çözüm

1
Calculate combinations of senior fellows and junior analysts to form the 6-person delegation.
Number of ways to choose 3 seniors out of 4 is (43)=4\binom{4}{3} = 4. Number of ways to choose 3 juniors out of 4 is (43)=4\binom{4}{3} = 4. Total selection combinations = 4×4=164 \times 4 = 16.
Choosing members from distinct pools uses combinations because member order within the selection does not matter.
2
Analyze the seating constraint for 3 seniors and 3 juniors around a 6-seat circular table.
The senior fellows must occupy alternating seats around the table (e.g., seats 1, 3, 5), leaving seats 2, 4, 6 for the junior analysts.
Placing 3 seniors among 6 circular seats with no two adjacent forces seniors to occupy every second seat.
3
Calculate the number of distinct circular seating arrangements for any specific set of 6 selected people.
Arrangements = (31)!×3!=2×6=12(3 - 1)! \times 3! = 2 \times 6 = 12.
To account for rotational symmetry at a circular table, fix one senior fellow's seat. The remaining 2 senior fellows can be seated in 2!=22! = 2 ways, and the 3 junior analysts can be seated in 3!=63! = 6 ways in the remaining open seats.
4
Apply the Fundamental Counting Principle to combine selection and seating steps.
Total arrangements = 16 (selections)×12 (seating arrangements)=19216 \text{ (selections)} \times 12 \text{ (seating arrangements)} = 192.
Each of the 16 unique delegations can be seated around the circular table in 12 distinct relative orders.

Anahtar Kavram

Combinations and Circular Permutations with Adjacency Restrictions
Tahmini Süre:2m 0s
Soru 154Soru

In the xyxy-plane, triangle ABCABC has vertices A(1,2)A(1, 2), B(4,2)B(4, 2), and C(1,6)C(1, 6). The triangle is reflected across the line y=xy = x, and then translated 22 units to the left and 33 units downward. What is the yy-coordinate of the image of vertex CC?

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Cevap: -2

Cevap

The y-coordinate of the image of vertex C is -2.
Reflecting a point (x,y)(x, y) across the line y=xy = x swaps the coordinates, transforming C(1,6)C(1, 6) into (6,1)(6, 1). Subsequently, translating the point 22 units to the left and 33 units downward subtracts 22 from the xx-coordinate and 33 from the yy-coordinate, resulting in (62,13)=(4,2)(6 - 2, 1 - 3) = (4, -2). The yy-coordinate of this image point is 2-2.

Adım Adım Çözüm

1
Apply reflection across the line y=xy = x to point C(1,6)C(1, 6).
The transformed point is C(6,1)C'(6, 1).
Reflecting a point (x,y)(x, y) across the line y=xy = x swaps its coordinates to (y,x)(y, x).
2
Apply translation left by 22 units and down by 33 units to C(6,1)C'(6, 1).
The final point is C(62,13)=C(4,2)C''(6 - 2, 1 - 3) = C''(4, -2).
Translating left subtracts from the xx-coordinate, and translating downward subtracts from the yy-coordinate.
3
Extract the yy-coordinate of C(4,2)C''(4, -2).
-2
The yy-coordinate is the second entry in the coordinate pair (x,y)(x, y).

Anahtar Kavram

Coordinate Geometry Transformations: Reflection across y = x and Translation
Tahmini Süre:1m 15s
Soru 155Soru

A dataset SS consists of 12 numbers listed in increasing order: x1,x2,,x12x_1, x_2, \dots, x_{12}. The median of dataset SS is 40. The arithmetic mean of the 6 smallest numbers in SS is 28, and the arithmetic mean of the 6 largest numbers in SS is 56. A new dataset TT is formed by subtracting 4 from each of the 6 smallest numbers in SS and adding 8 to each of the 6 largest numbers in SS. What is the positive difference between the arithmetic mean of dataset TT and the median of dataset TT?

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Cevap: 2

Cevap

2
The total sum of dataset S is 504, giving a mean of 42. Transforming the elements adds a net total of 24 to the overall sum, so the mean of dataset T becomes 44. Because decreasing the lower half and increasing the upper half preserves the relative sorted order of all 12 numbers, the middle two elements of dataset T are x_6 - 4 and x_7 + 8. Thus, the new median is (x_6 + x_7)/2 + 2 = 40 + 2 = 42. The positive difference between the mean of 44 and the median of 42 is 2.

Adım Adım Çözüm

1
Calculate the arithmetic mean of the original dataset SS.
The sum of the 6 smallest numbers is 6×28=1686 \times 28 = 168, and the sum of the 6 largest numbers is 6×56=3366 \times 56 = 336. The total sum of dataset SS is 168+336=504168 + 336 = 504. Thus, the mean of SS is 50412=42\frac{504}{12} = 42.
The mean of a dataset is the sum of all elements divided by the total number of elements.
2
Calculate the arithmetic mean of the new dataset TT.
The sum of dataset TT is 504+6(4)+6(8)=50424+48=528504 + 6(-4) + 6(8) = 504 - 24 + 48 = 528. The mean of dataset TT is 52812=44\frac{528}{12} = 44.
Modifying each of the 12 elements changes the overall sum by the sum of individual changes.
3
Determine the median of the new dataset TT.
Since x6<x7x_6 < x_7, after transformations x64<x7+8x_6 - 4 < x_7 + 8. The relative order of all elements is preserved. The median of TT is (x64)+(x7+8)2=x6+x72+2=40+2=42\frac{(x_6 - 4) + (x_7 + 8)}{2} = \frac{x_6 + x_7}{2} + 2 = 40 + 2 = 42.
The median of an even number of ordered elements is the average of the two middle elements.
4
Calculate the positive difference between the mean and median of dataset TT.
|44 - 42| = 2.
Subtract the median from the mean and take the absolute value.

Anahtar Kavram

Effect of linear transformations and subgroup operations on the mean and median of ordered datasets
Soru 156Soru

In the xyxy-plane, line kk is defined by the equation 3x4y=123x - 4y = 12. Line mm is parallel to line kk, and the perpendicular distance between line kk and line mm is 55 units. If the yy-intercept of line mm is greater than the yy-intercept of line kk, what is the yy-intercept of line mm?

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Cevap: 3.25

Cevap

3.25
Rewriting line kk as 3x4y12=03x - 4y - 12 = 0 shows its yy-intercept is 3-3. Line mm is parallel, so its equation is 3x4y+C=03x - 4y + C = 0. Using the formula for perpendicular distance between parallel lines d=C1C2A2+B2d = \frac{|C_1 - C_2|}{\sqrt{A^2 + B^2}}, we have 12C32+(4)2=5\frac{|-12 - C|}{\sqrt{3^2 + (-4)^2}} = 5. This simplifies to 12C=25|-12 - C| = 25, giving C=13C = 13 or C=37C = -37. Setting x=0x = 0 for line mm gives y=C4=C4y = -\frac{C}{-4} = \frac{C}{4}. For C=13C = 13, the yy-intercept is 134=3.25\frac{13}{4} = 3.25. Since 3.25>33.25 > -3, this meets all criteria.

Adım Adım Çözüm

1
Find the yy-intercept of line kk
Line kk has a yy-intercept at (0,3)(0, -3).
Setting x=0x = 0 in 3x4y=123x - 4y = 12 gives 4y=12    y=3-4y = 12 \implies y = -3.
2
Formulate the general equation for line mm
Line mm has the equation 3x4y+C=03x - 4y + C = 0.
Parallel lines share the same linear coefficients A=3A = 3 and B=4B = -4.
3
Set up the distance formula between parallel lines
12C5=5\frac{|-12 - C|}{5} = 5
The distance between Ax+By+C1=0Ax + By + C_1 = 0 and Ax+By+C2=0Ax + By + C_2 = 0 is d=C1C2A2+B2d = \frac{|C_1 - C_2|}{\sqrt{A^2 + B^2}}.
4
Solve for constant CC
C=13C = 13 or C=37C = -37
12C=25|-12 - C| = 25 yields 12C=25    C=37-12 - C = 25 \implies C = -37 and 12C=25    C=13-12 - C = -25 \implies C = 13.
5
Determine the required yy-intercept
y=3.25y = 3.25
For C=13C = 13, the yy-intercept is 134=3.25\frac{13}{4} = 3.25, which is greater than 3-3.

Anahtar Kavram

Perpendicular distance between parallel lines and line intercept calculation
Tahmini Süre:2m 30s
Soru 157Soru

In right triangle ABCABC, the measure of angle ACBACB is 9090^\circ. Altitude CDCD is drawn from vertex CC to hypotenuse ABAB, with point DD lying on line segment ABAB. If AD=9AD = 9 and DB=16DB = 16, what is the perimeter of triangle ABCABC?

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Cevap: 60

Cevap

The perimeter of triangle ABCABC is 60.
By the Geometric Mean Theorem for right triangles, the altitude CDCD to hypotenuse ABAB satisfies CD2=ADDB=916=144CD^2 = AD \cdot DB = 9 \cdot 16 = 144, giving CD=12CD = 12. Applying the Pythagorean Theorem to the smaller right triangles ADC\triangle ADC and BDC\triangle BDC yields AC=92+122=15AC = \sqrt{9^2 + 12^2} = 15 and BC=162+122=20BC = \sqrt{16^2 + 12^2} = 20. The hypotenuse AB=9+16=25AB = 9 + 16 = 25. Summing the side lengths gives the perimeter: 15+20+25=6015 + 20 + 25 = 60.

Adım Adım Çözüm

1
Calculate the length of altitude CDCD using the Geometric Mean Theorem.
CD=ADDB=916=144=12CD = \sqrt{AD \cdot DB} = \sqrt{9 \cdot 16} = \sqrt{144} = 12
In a right triangle, the altitude to the hypotenuse divides the hypotenuse into two segments such that the altitude is the geometric mean of the two segment lengths.
2
Calculate leg ACAC using the Pythagorean Theorem in right triangle ADCADC.
AC=AD2+CD2=92+122=81+144=225=15AC = \sqrt{AD^2 + CD^2} = \sqrt{9^2 + 12^2} = \sqrt{81 + 144} = \sqrt{225} = 15
Triangle ADCADC is a right triangle with right angle at DD (3453-4-5 triple scaled by 33).
3
Calculate leg BCBC using the Pythagorean Theorem in right triangle BDCBDC.
BC=BD2+CD2=162+122=256+144=400=20BC = \sqrt{BD^2 + CD^2} = \sqrt{16^2 + 12^2} = \sqrt{256 + 144} = \sqrt{400} = 20
Triangle BDCBDC is a right triangle with right angle at DD (3453-4-5 triple scaled by 44).
4
Calculate the total perimeter of triangle ABCABC.
Perimeter = AC+BC+AB=15+20+(9+16)=15+20+25=60AC + BC + AB = 15 + 20 + (9 + 16) = 15 + 20 + 25 = 60
The perimeter is the sum of the three outer sides of triangle ABCABC.

Anahtar Kavram

Right Triangle Altitude Relationships and Pythagorean Triples
Soru 158Soru

A box contains 1010 cards: 44 blue cards numbered 1,2,3,51, 2, 3, 5 and 66 red cards numbered 1,2,3,4,6,81, 2, 3, 4, 6, 8. Two cards are drawn sequentially at random without replacement from the box. Let AA be the event that the first card drawn is blue, and let BB be the event that the sum of the numbers on the two drawn cards is an even number. What is the value of the conditional probability P(AB)P(A \mid B)?

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Cevap: 0.4

Cevap

0.4 (or 2/5)
The conditional probability P(AB)P(A \mid B) represents the likelihood that the first card drawn was blue given that the sum of the two drawn cards is even. There are 40 total outcome pairs resulting in an even sum (20 where both are odd and 20 where both are even). Among these 40 outcomes, exactly 16 start with a blue card (12 starting with a blue odd card and 4 starting with a blue even card). Therefore, P(AB)=1640=0.4P(A \mid B) = \frac{16}{40} = 0.4.

Adım Adım Çözüm

1
Classify the sample space of cards by color and number parity.
Blue cards consist of 3 odds (1, 3, 5) and 1 even (2). Red cards consist of 2 odds (1, 3) and 4 evens (2, 4, 6, 8). Across all 10 cards, there are 5 odd cards and 5 even cards.
Categorizing by parity is essential because the sum of two integers is even if and only if both numbers share the same parity (both odd or both even).
2
Calculate the total number of sequential draw outcomes belonging to event BB (sum is even).
Number of (Odd, Odd) outcomes = 5×4=205 \times 4 = 20. Number of (Even, Even) outcomes = 5×4=205 \times 4 = 20. Total outcomes for event BB, N(B)=20+20=40N(B) = 20 + 20 = 40.
Since draws are without replacement, drawing a card reduces the available count of that parity by 1 for the second draw.
3
Calculate the number of outcomes belonging to the joint event ABA \cap B (first card is blue AND sum is even).
Subcase 1 (Blue Odd 1st, Odd 2nd): 3×4=123 \times 4 = 12 outcomes. Subcase 2 (Blue Even 1st, Even 2nd): 1×4=41 \times 4 = 4 outcomes. Total outcomes for ABA \cap B, N(AB)=12+4=16N(A \cap B) = 12 + 4 = 16.
To satisfy both event AA (first card blue) and event BB (even sum), the second card must match the parity of the selected blue card.
4
Compute the conditional probability P(AB)P(A \mid B).
P(AB)=N(AB)N(B)=1640=25=0.4P(A \mid B) = \frac{N(A \cap B)}{N(B)} = \frac{16}{40} = \frac{2}{5} = 0.4.
By the definition of conditional probability, P(AB)=P(AB)P(B)=N(AB)N(B)P(A \mid B) = \frac{P(A \cap B)}{P(B)} = \frac{N(A \cap B)}{N(B)} when all outcomes in the reduced sample space are equally likely.

Anahtar Kavram

Conditional Probability and Sequential Dependent Sampling
Soru 159Soru

The quadratic function f(x)=2x2+kx18f(x) = -2x^2 + kx - 18 has a maximum value of 1414, where kk is a positive constant. What is the value of kk?

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Cevap: 16

Cevap

The value of kk is 1616.
The vertex of the parabola f(x)=2x2+kx18f(x) = -2x^2 + kx - 18 is located at x=k4x = \frac{k}{4}. Evaluating f(k4)f\left(\frac{k}{4}\right) gives the maximum value k2818\frac{k^2}{8} - 18. Setting this expression equal to 1414 leads to k28=32\frac{k^2}{8} = 32, so k2=256k^2 = 256. Taking the positive root as required by the problem statement yields k=16k = 16.

Adım Adım Çözüm

1
Find the xx-coordinate of the vertex of the quadratic function.
For f(x)=2x2+kx18f(x) = -2x^2 + kx - 18, we have a=2a = -2, b=kb = k, and c=18c = -18. The vertex occurs at x=b2a=k2(2)=k4x = -\frac{b}{2a} = -\frac{k}{2(-2)} = \frac{k}{4}.
The maximum or minimum of any quadratic function ax2+bx+cax^2 + bx + c occurs at its vertex, where x=b2ax = -\frac{b}{2a}.
2
Evaluate the function at the vertex to determine the maximum value in terms of kk.
f(k4)=2(k4)2+k(k4)18=2(k216)+k2418=k28+k2418=k2818f\left(\frac{k}{4}\right) = -2\left(\frac{k}{4}\right)^2 + k\left(\frac{k}{4}\right) - 18 = -2\left(\frac{k^2}{16}\right) + \frac{k^2}{4} - 18 = -\frac{k^2}{8} + \frac{k^2}{4} - 18 = \frac{k^2}{8} - 18.
Substituting the vertex xx-coordinate into f(x)f(x) yields the maximum value of the downward-opening parabola.
3
Set the maximum value expression equal to 1414 and solve for k2k^2.
\frac{k^2}{8} - 18 = 14 \implies \frac{k^2}{8} = 32 \implies k^2 = 256.
The problem states that the maximum value of f(x)f(x) is 1414.
4
Solve for the positive constant kk.
k=256=16.k = \sqrt{256} = 16.
Taking the square root of 256256 gives k=16k = 16 or k=16k = -16. Since kk is given as a positive constant, k=16k = 16.

Anahtar Kavram

Finding the extreme value of a quadratic function by locating its vertex
Soru 160Soru

A committee of 55 members is to be selected from a pool of 66 doctors and 44 nurses. How many different 55-member committees can be formed that contain at least 33 doctors?

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Cevap: 186

Cevap

186
To form a 5-member committee containing at least 3 doctors from 6 doctors and 4 nurses, consider the three mutually exclusive possibilities: 3 doctors and 2 nurses, 4 doctors and 1 nurse, or 5 doctors and 0 nurses. Using combinations, the number of ways for each case are 120, 60, and 6 respectively. Summing these gives 186 distinct committees.

Adım Adım Çözüm

1
Determine all valid committee compositions meeting the requirement
The committee can consist of: 3 doctors and 2 nurses, 4 doctors and 1 nurse, or 5 doctors and 0 nurses.
The prompt specifies 'at least 3 doctors' out of 5 total members.
2
Calculate the combinations for each scenario
Case 1: \(\binom{6}{3} \times \binom{4}{2} = 20 \times 6 = 120\)
Case 2: \(\binom{6}{4} \times \binom{4}{1} = 15 \times 4 = 60\)
Case 3: \(\binom{6}{5} \times \binom{4}{0} = 6 \times 1 = 6\)
Order of selection does not matter, so combination formula \(\binom{n}{k}\) is used.
3
Sum the valid combinations
120 + 60 + 6 = 186
The scenarios are mutually exclusive, so the addition principle applies.

Anahtar Kavram

Combinations with restrictions and Addition Principle
ÖncekiSayfa 8 / 12Sonraki
Tüm alıştırma soruları — GRE General Test | Examkin