Correct Answer: A

Rationale: To convert tons to pounds, you multiply by 2000 because 1 ton is equal to 2000 pounds. Therefore, 3 tons equal 3 2000 = 6000 pounds. The correct answer is 6000 pounds. Choice B (5000 pounds) is incorrect because it miscalculates the conversion. Choice C (3000 pounds) is incorrect as it represents the weight of 1 ton, not 3 tons. Choice D (7000 pounds) is incorrect as it overestimates the weight of 3 tons.

Correct Answer: C

Rationale: Reducing the rat's speed by 50% means it will take twice as long to finish the maze. Since the original time is 3 minutes, doubling that gives 6 minutes. Therefore, the total time will be 6 minutes, making the correct answer C. Choice A (3 minutes) is the original time it takes the rat to finish the maze, not the time with the backpack. Choice B (4 minutes) is not correct as reducing the speed by 50% would double the original time. Choice D (1.5 minutes) is incorrect as halving the time is not the effect of reducing the speed by 50%.

Correct Answer: C

Rationale: To find the percentage of 8 in 40, divide 8 by 40 to get 0.2. Multiply this result by 100 to convert it to a percentage: 0.2 100 = 10%. Therefore, 8 is 10% of 40, making choice C the correct answer. Choices A, B, and D are incorrect percentages calculated from incorrect divisions and multiplications.

Correct Answer: A

Rationale: To multiply decimals, align the numbers as whole numbers, multiply as if they were whole numbers, then adjust the decimal point in the final answer. When multiplying 0.67 by 0.09, the result is 0.0603. To get this result, multiply 67 by 9 to get 603, then adjust the decimal point two places to the left in the final product, resulting in 0.0603. Choice B, 0.6, is incorrect because it does not account for the decimal precision in the multiplication. Choice C, 0.603, is incorrect as it has the digits reversed when compared to the correct answer. Choice D, 0.06, is incorrect as it does not reflect the correct product of the two decimals being multiplied.

Correct Answer: B

Rationale: To find the percentage of brown horses, first calculate the total number of horses: 10 black + 6 brown + 8 two-color + 3 all white = 27 horses. Then, calculate the percentage of brown horses: (6 · 27) 100 = 22.22%, which rounds to 20%. Choice B, 20%, is the correct answer. Choice A, 15%, is incorrect as it does not reflect the accurate percentage of brown horses. Choice C, 25%, is incorrect as it overestimates the percentage of brown horses. Choice D, 30%, is incorrect as it also overestimates the percentage of brown horses.