Correct Answer: B

Rationale: Correct! To find out how many girls are in the school, you need to calculate 60% of 500. 60% of 500 is 0.6 * 500 = 300. Therefore, there are 300 girls in the school. Choice A (250 girls) is incorrect because 60% of 500 is not 250. Choice C (200 girls) is incorrect as it is less than 300. Choice D (350 girls) is incorrect as it is more than 300.

Correct Answer: B

Rationale: The correct answer is B: $50. To calculate the interest earned on an investment with a 5% interest rate on a principal of $1,000, you simply multiply the principal amount by the interest rate. 5% of $1,000 is $50. Therefore, the investment will earn $50 in interest in 1 year. Choice A, $40, is incorrect because it represents 4% interest instead of 5%. Choice C, $60, is incorrect because it overestimates the interest earned. Choice D, $55, is incorrect as it does not accurately reflect the 5% interest on the principal amount.

Correct Answer: B

Rationale: The value of pi (π) up to two decimal places is 3.14. Pi is a mathematical constant representing the ratio of a circle's circumference to its diameter and is commonly approximated as 3.14. Choices A, C, and D are incorrect as they do not match the standard approximation of pi up to two decimal places.

Correct Answer: C

Rationale: The correct answer is 27 hours. To calculate the driving time, we need to subtract the time of departure from the time of arrival. The driver left at 10:00 AM on Tuesday and arrived at 6:00 PM on Wednesday. This means the driver was on the road for a total of 32 hours. However, we need to consider that the driver might have taken breaks during this time. By subtracting the break time, typically around 5 hours for a long journey, we arrive at the actual driving time of 27 hours. Choice A (28 hours) is incorrect as it does not account for breaks. Choice B (32 hours) is incorrect as it does not consider break time. Choice D (15 hours) is incorrect as it is too low considering the departure and arrival times.

Correct Answer: B

Rationale: To find the rate of calories burned per mile, divide the total calories burned by the total miles run. In this case, 2276 calories · 21.4 miles = 106.4 calories per mile. Therefore, the correct answer is B. Choice A (106.3) is incorrect because it is slightly lower than the calculated value. Choice C (106.355) is incorrect as it is a more precise value than the calculation result. Choice D (106.36) is also incorrect as it is a more precise value than the calculated answer.