Using the chart below, which equation describes the relationship between x and y?
- A. x = 3y
- B. y = 3x
- C. y = 1/3x
- D. x/y = 3
Correct Answer: B
Rationale: The correct equation that describes the relationship between x and y based on the chart is y = 3x. This is because each y-value in the chart is 3 times the x-value. Choice A (x = 3y) is incorrect as it implies x is 3 times y, which is the opposite of the relationship shown in the chart. Choice C (y = 1/3x) is incorrect since the relationship in the chart indicates y is 3 times x, not a third of x. Choice D (x/y = 3) is incorrect as it represents a ratio between x and y equal to 3, which is not in line with the relationship depicted in the chart.
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What is the number of students who said their favorite color is blue if 35% of 100 students chose blue as their favorite color?
- A. 35
- B. 25
- C. 20
- D. 10
Correct Answer: A
Rationale: To find the number of students who said their favorite color is blue, we calculate 35% of 100, which is (35/100) * 100 = 35. Therefore, 35 students said their favorite color is blue. Choice B is incorrect because it represents the percentage of students who chose red. Choice C is incorrect as it represents the percentage of students who chose green. Choice D is incorrect as it represents the percentage of students who chose yellow.
A farmer had about 150 bags of potatoes on his trailer. Each bag contained from 23 to 27 pounds of potatoes. What is the best estimate of the total number of pounds of potatoes on the farmer's trailer?
- A. 3,000 pounds
- B. 3,700 pounds
- C. 4,100 pounds
- D. 5,000 pounds
Correct Answer: B
Rationale: To estimate the total number of pounds of potatoes on the farmer's trailer, we can use the average weight of a bag of potatoes. The average weight is calculated by adding the minimum and maximum weights of the bags and dividing by 2: (23 + 27) / 2 = 25 pounds. Next, multiply the average weight by the total number of bags: 25 pounds/bag * 150 bags = 3,750 pounds. Therefore, the best estimate of the total number of pounds of potatoes on the farmer's trailer is 3,750 pounds. Choice A (3,000 pounds) is too low as it underestimates the total weight. Choice C (4,100 pounds) and Choice D (5,000 pounds) are too high as they overestimate the total weight.
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.
A lab technician took 100 hairs from a patient to conduct several tests. The technician used 1/7 of the hairs for a drug test. How many hairs were used for the drug test? (Round your answer to the nearest hundredth.)
- A. 14
- B. 14.2
- C. 14.29
- D. 14.3
Correct Answer: C
Rationale: To find how many hairs were used for the drug test, you need to calculate 1/7 of 100. 1/7 of 100 is 14.2857, which rounds to 14.29 when rounded to the nearest hundredth. Therefore, 14.29 hairs were used for the drug test. Choice A is incorrect as it does not account for rounding to the nearest hundredth. Choices B and D are incorrect as they do not accurately reflect the calculated value after rounding.
Jeremy put a heavy chalk mark on the tire of his bicycle. His bike tire is 27 inches in diameter. When he rolled the bike, the chalk left marks on the sidewalk. Which expression can be used to best determine the distance, in inches, the bike rolled from the first mark to the fourth mark?
- A. 3(27π)
- B. 4π(27)
- C. (27 · 3)π
- D. (27 · 4)π
Correct Answer: A
Rationale: The distance traveled by the bike in one complete roll of the tire is equal to the circumference, which can be calculated using the formula C = πd, where d is the diameter. Given that the diameter of the bike tire is 27 inches, the circumference is obtained by multiplying the diameter by π. As the tire rolls from the first mark to the fourth mark, it completes three full rotations (one complete roll plus two more). Therefore, the total distance rolled is 3 times the circumference, which results in 3(27π). Choice A is correct. Choice B is incorrect as it incorrectly multiplies the diameter by 4π instead of multiplying the circumference by 4. Choices C and D are incorrect as they involve dividing the diameter by a number, which is not applicable in this context.