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What was the mean time for the women who ran the 200m event at the 2008 Olympic Games (times in seconds: 22.33, 22.50, 22.50, 22.61, 22.71, 22.72, 22.83, 23.22)?
- A. 22.50 sec
- B. 22.66 sec
- C. 22.68 sec
- D. 22.77 sec
Correct Answer: C
Rationale: To find the mean time, you need to add all the times (22.33 + 22.50 + 22.50 + 22.61 + 22.71 + 22.72 + 22.83 + 23.22) and then divide by the total number of times (8). This calculation results in a mean time of 22.68 seconds. Choice A, 22.50 sec, is incorrect because it is the time of one of the runners, not the mean time. Choice B, 22.66 sec, and Choice D, 22.77 sec, are also incorrect as they are not the calculated mean of the given times.
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Robert scores three new clients every eight months. After how many months has he secured 24 new clients?
- A. 64
- B. 58
- C. 52
- D. 66
Correct Answer: A
Rationale: To find out the number of months needed to secure 24 new clients, you can set up a proportion: 3 clients / 8 months = 24 clients / x months. Cross multiplying gives you 3x = 24 * 8. Solving for x: 3x = 192, x = 192 / 3, x = 64. Therefore, Robert will secure 24 new clients after 64 months. Choice A is correct. Choice B (58), Choice C (52), and Choice D (66) are incorrect as they do not align with the correct calculation based on the given proportion.
The table below shows the number of books checked out from a library over the course of 4 weeks. Which equation describes the relationship between the number of books (b) and weeks (w)?
- A. b = 10w + 2
- B. b = 5w + 10
- C. b = 8w + 12
- D. b = 4w + 20
Correct Answer: B
Rationale: The relationship between the number of books and weeks is best described by the equation b = 5w + 10. This is because the initial value of books checked out is 10, which indicates that even with 0 weeks, there are already 10 books checked out. The rate at which books are checked out per week is 5, as indicated by the coefficient of w. Therefore, the correct equation should be b = 5w + 10. Choices A, C, and D are incorrect because they do not represent the correct initial value or rate of increase for the given scenario.
A gift box has a length of 14 inches, a height of 8 inches, and a width of 6 inches. How many square inches of wrapping paper are needed to wrap the box?
- A. 56
- B. 244
- C. 488
- D. 672
Correct Answer: C
Rationale: To find the surface area of a rectangular prism, you use the formula SA = 2lw + 2wh + 2hl, where l is the length, w is the width, and h is the height. Substituting the given dimensions, the calculation would be SA = 2(14)(6) + 2(6)(8) + 2(8)(14) = 168 + 96 + 224 = 488 square inches. Therefore, 488 square inches of wrapping paper are needed to wrap the box. Choice A (56), Choice B (244), and Choice D (672) are incorrect because they do not represent the correct surface area calculation for the given box dimensions.
Jonathan pays a $65 monthly flat rate for his cell phone. He is charged $0.12 per minute for each minute used in a roaming area. Which of the following expressions represents his monthly bill for x roaming minutes?
- A. 65 + 0.12x
- B. 65x + 0.12
- C. 65.12x
- D. 65 + 0.12x
Correct Answer: A
Rationale: The correct expression for Jonathan's monthly bill is 65 + 0.12x, where x represents the number of roaming minutes. The $65 monthly flat rate is added to the product of $0.12 per minute and the number of roaming minutes (x). Choice B is incorrect because it incorrectly multiplies the flat rate by x and adds the per-minute charge. Choice C is incorrect as it combines the flat rate and the per-minute charge into a single value. Choice D is incorrect as it incorrectly multiplies the flat rate by x and adds the per-minute charge separately.
The cost of renting a car is $50 per day plus $0.25 per mile driven. If a customer rents the car for 3 days and drives 120 miles, what is the total cost?
- A. $156
- B. $190
- C. $165
- D. $210
Correct Answer: A
Rationale: To calculate the total cost, first, multiply the number of days by the cost per day: 3 days x $50/day = $150. Then, multiply the number of miles driven by the cost per mile: 120 miles x $0.25 = $30. Finally, add the two amounts together: $150 (daily cost) + $30 (mileage cost) = $180. Therefore, the correct total cost is $180, which corresponds to choice A. The other choices are incorrect because they do not reflect the accurate calculation of $150 for the daily cost and $30 for the mileage cost.