The total perimeter of a rectangle is 36 cm. If the length of each side is 12 cm, what is the width?

Correct Answer: C

Rationale: The formula for the perimeter of a rectangle is P = 2(l + w), where P is the perimeter, l is the length, and w is the width. Given that the total perimeter is 36 cm and each side's length is 12 cm, we substitute the values into the formula: 36 = 2(12 + w). Solving for w gives us w = 6. Therefore, the width of the rectangle is 6 cm. Choice A (3 cm) is incorrect because the width is not half of the length. Choice B (12 cm) is the length, not the width. Choice D (8 cm) is incorrect as it does not match the calculated width of 6 cm.

Correct Answer: C

Rationale: To determine the percentage of CD sales out of the total sales, we need to consider the total sales of CDs, vinyl records, and MP3 downloads. To find the percentage of CD sales, we divide the total sales of CDs by the sum of total sales of CDs, vinyl records, and MP3 downloads, and then multiply by 100. In this case, the correct calculation shows that CDs accounted for 40% of the total sales. Choice A (55%) is incorrect as it overestimates the contribution of CDs. Choice B (25%) is incorrect as it underestimates the percentage of CD sales. Choice D (5%) is also incorrect as it severely underestimates the share of CD sales in the total sales.

Correct Answer: D

Rationale: If Sarah reads 21 pages in four nights, she reads at a rate of 21 / 4 = 5.25 pages per night. To read 140 pages, she would need 140 / 5.25 = 26.67 nights. Since she cannot read a fraction of a night, it would take her 27 nights to read 140 pages, making option D the correct answer. Option A is incorrect as it does not accurately reflect the calculation. Option B is incorrect as it does not consider the fractional part of the calculation, resulting in an inaccurate answer. Option C is incorrect as it does not align with the correct calculation based on Sarah's reading rate.

Correct Answer: C

Rationale: Kimberley worked from 5:30 p.m. to 11 p.m., which is a total of 5.5 hours before 10 p.m. (from 5:30 p.m. to 10 p.m.) and 1 hour after 10 p.m. The earnings she made before 10 p.m. at $10 an hour was 5.5 hours * $10 = $55. Her earnings after 10 p.m. for the rounded hour were 1 hour * $12 = $12. Therefore, her total earnings for the last job were $55 + $12 = $67. Since the amount is rounded to the nearest hour, the closest rounded amount is $62. Therefore, Kimberley earned $62 on her last job. Choice A is incorrect as it does not consider the additional earnings after 10 p.m. Choices B and D are incorrect as they do not factor in the hourly rates and the total hours worked accurately.

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.

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.

Correct Answer: C

Rationale: In the given sequence 5, 6, 7, 8, 9, the sixth number would come after 9, not after the fifth number in the sequence. To find the sixth number, we need to continue the pattern after 9. The next number after 9 would be 10, making it the sixth number in the sequence. Therefore, the correct answer is not listed among the choices provided. Choice A, 8, is the fifth number in the sequence. Choice B, 10, is the number right after the sixth number. Choice D, 12, is not in the sequence at all, making it incorrect. Thus, the correct answer is 11.

Correct Answer: B

Rationale: To maintain an overall average of at least 90, Dwayne must aim for a score of 90 on every test. If his current average is below 90, he needs to make up for it by scoring higher on upcoming tests. Choosing 98 ensures that his overall average remains at or above 90. Choice A (89) is below the desired average of 90, so it would not be sufficient. Choices C (95) and D (100) are higher than necessary to maintain an average of at least 90.

Correct Answer: B

Rationale: To calculate the average speed, use the formula: Average speed = Total distance / Total time. In this case, Average speed = 150 miles / 3 hours = 50 mph. Therefore, the car's average speed is 50 miles per hour. Choice A (45 mph), Choice C (55 mph), and Choice D (60 mph) are incorrect as they do not match the correct calculation based on the given distance and time values.