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: A

Rationale: To determine the initial amount she had, we subtract the amount spent ($18) from the total amount she had after spending. If she had $1,070 after spending, subtracting $18 gives us $1,052, which was the initial amount. Choices B, C, and D are incorrect as they do not consider the subtraction of the amount spent to find the initial amount.

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: 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: 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.