67 miles is equivalent to how many kilometers to three significant digits?
- A. 107 km
- B. 106 km
- C. 33 km
- D. 85 km
Correct Answer: A
Rationale: To convert miles to kilometers, the conversion factor is 1 mile ≈ 1.609 kilometers. Therefore, to convert 67 miles to kilometers, you would multiply: 67 miles 1.609 km/mile = 107.703 km. When rounded to three significant digits, this gives 108 km. Therefore, 67 miles is approximately 108 kilometers. Choice A is correct because it is the closest rounded value to three significant digits. Choices B, C, and D are incorrect as they do not match the calculated conversion of 108 km.
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How much did he save from the original price?
- A. $170
- B. $212.50
- C. $105.75
- D. $200
Correct Answer: B
Rationale: To calculate the amount saved from the original price, you need to subtract the discounted price from the original price. The formula is: Original price - Discounted price = Amount saved. In this case, the original price was $850, and the discounted price was $637.50. Therefore, $850 - $637.50 = $212.50. Hence, he saved $212.50 from the original price. Choice A ($170) is incorrect as it is not the correct amount saved. Choice C ($105.75) is incorrect as it does not match the calculated savings. Choice D ($200) is incorrect as it is not the accurate amount saved based on the given prices.
Adrian measures the circumference of a circular picture frame with a radius of 3 inches. Which of the following is the best estimate for the circumference of the frame?
- A. 12 inches
- B. 16 inches
- C. 18 inches
- D. 24 inches
Correct Answer: C
Rationale: To calculate the circumference of a circle, use the formula 2πr, where r is the radius. In this case, with a radius of 3 inches, the estimated circumference would be 2 x π x 3 = 6π ≈ 18.85 inches. Therefore, the best estimate for the circumference of the frame is 18 inches (Choice C). Choice A (12 inches) is too small as it corresponds to the diameter rather than the circumference. Choice B (16 inches) and Choice D (24 inches) are also incorrect as they do not reflect the accurate calculation based on the given radius.
What is 4.6 rounded to the nearest integer?
- A. 3
- B. 4
- C. 5
- D. 6
Correct Answer: C
Rationale: When rounding a decimal number to the nearest integer, if the decimal part is 0.5 or greater, we round up to the next integer; if it is less than 0.5, we round down. In this case, 4.6 is closer to 5 than to 4 because it is exactly halfway between the two integers. Therefore, when rounding 4.6 to the nearest integer, we round up to 5. Choice A (3), B (4), and D (6) are incorrect as they are not the nearest integer to 4.6.
When rounding 2678 to the nearest thousandth, which place value would be used to decide whether to round up or round down?
- A. Ten-thousandth
- B. Thousandth
- C. Hundredth
- D. Thousand
Correct Answer: B
Rationale: When rounding 2678 to the nearest thousandth, you would look at the digit in the thousandth place, which is 7. To decide whether to round up or down, you consider the digit to the immediate right of the place you are rounding to. Since 7 is equal to or greater than 5, you round up. Choice A, ten-thousandth, is incorrect as we are rounding to the thousandth place. Choice C, hundredth, is not relevant as we are not rounding to that place value. Choice D, thousand, is incorrect as it is the original number being rounded, not the place value used for rounding.
A school has 15 teachers and 20 teaching assistants. They have 200 students. What is the ratio of faculty to students?
- A. 3:20
- B. 4:17
- C. 3:02
- D. 7:40
Correct Answer: B
Rationale: The total number of faculty members is 15 teachers + 20 teaching assistants = 35. The ratio of faculty to students is then 35:200, which simplifies to 7:40. Further simplifying by dividing both numbers by 5 gives the ratio 4:20, which can be simplified to 4:17. Therefore, the correct ratio is 4:17. Choices A, C, and D are incorrect ratios and do not match the calculated ratio of faculty members to students in this scenario.