A child's toy block is a cube with side lengths of 5cm. What is its total surface area?

Correct Answer: D

Rationale: The surface area of a cube is calculated using the formula: 6 * (side length)^2. Substituting the side length of 5cm into the formula, we get: 6 * (5cm)^2 = 6 * 25cm^2 = 150 sq cm. Therefore, the total surface area of the toy block is 150 sq cm. Choices A (25 sq cm), B (50 sq cm), and C (125 sq cm) are incorrect as they do not correctly calculate the total surface area of the cube.

Correct Answer: C

Rationale: To multiply 25 by 4, you get 100. To express the result in decimal form, you divide by 100. Therefore, the result is 1. Choice A (0.01) is incorrect as it represents 1/100, not the result of 25 4. Choice B (0.1) is incorrect as it represents 1/10. Choice D (10) is incorrect as it is the result before converting it to decimal form.

Correct Answer: B

Rationale: To determine the tip percentage left, divide the tip amount ($36) by the total bill amount ($200), then multiply the result by 100 to express it as a percentage: (36/200) x 100 = 18%. Therefore, he left an 18% tip on the total bill amount. Choice A (16%) is incorrect because the correct calculation results in 18%. Choice C (20%) and Choice D (22%) are incorrect as they do not match the calculated percentage based on the provided numbers.

Correct Answer: C

Rationale: Let X be Bai Lin's monthly paycheck. From the given information, she puts 10% of X in savings and spends 30% on living expenses. This means she retains 60% (100% - 10% - 30%) of her paycheck, which equals $1,545. Therefore, 60% of X is $1,545. To find X, we divide $1,545 by 60% (or 0.60), which gives us X = $2,575. Hence, Bai Lin's monthly paycheck is $2,575. Therefore, the correct answer is $2,575. Choices A, B, and D are incorrect because they do not match the calculated monthly paycheck based on the given percentages and remaining amount.

Correct Answer: C

Rationale: To convert miles to kilometers, you can use the conversion factor of 1 mile is equal to 1.609 kilometers. Therefore, to find the number of kilometers in 12 miles, you can multiply 12 miles by 1.609 to get 19.2 kilometers. The correct answer is 19.2 kilometers, making choice C the correct option. Choice A (7.5 kilometers) is incorrect because it represents half the correct conversion. Choice B (13.2 kilometers) is incorrect as it does not apply the correct conversion factor. Choice D (22 kilometers) is incorrect and represents an incorrect conversion calculation.

Correct Answer: A

Rationale: In Roman numerals, 1776 is correctly written as MDCCLXXVI. Here's the breakdown: M (1000) + D (500) + CCC (300) + L (50) + XX (20) + VI (6) = 1776. Therefore, the correct Roman numeral representation of the date 1776 is MDCCLXXVI. Choice A is correct because it follows the correct Roman numeral rules for representing 1776. Choices B, C, and D are incorrect as they do not add up to 1776 according to Roman numeral conventions.

Correct Answer: B

Rationale: Rationale: 1. Let x be the volume of the 10% solution needed and y be the volume of water needed. 2. The total volume of the final solution is 200ml, so x + y = 200. 3. The concentration of the final solution is 5%, so the amount of salt in the final solution is 0.05 * 200 = 10g. 4. The amount of salt in the 10% solution is 0.1x, and the amount of salt in the water is 0, so the total amount of salt in the final solution is 0.1x. 5. Since the total amount of salt in the final solution is 10g, we have 0.1x = 10. 6. Solving for x, we get x = 100ml. 7. Substituting x =

Correct Answer: B

Rationale: After spending $6.50 on a sandwich, the man had $3.50 left. Then, after spending $1.80 on a drink, he had $1.70 left. Finally, he spent another $0.75 on a bag of chips. Subtracting $0.75 from $1.70 gives us $0.95, which is the amount of money he had left. Choice A is incorrect because it does not consider the bag of chips he bought. Choice C is incorrect as it miscalculates the remaining amount. Choice D is incorrect as it does not account for the total expenses.

Correct Answer: B

Rationale: To convert pounds to kilograms, you can use the conversion factor: 1 pound is approximately equal to 0.453592 kilograms. Therefore, 11 pounds is equal to 11 * 0.453592 = 4.989512, which is approximately 5.5 kilograms. The correct answer is 5.5 kilograms. Choice A is incorrect as it rounds down and doesn't account for the decimals in the conversion. Choices C and D are significantly higher than the correct answer and are clearly incorrect conversions.