Correct Answer: D

Rationale: To find the sale price after a 30% discount, you need to subtract 30% of the original price from the original price. 30% of $472 is $141.60. Subtracting this discount from the original price gives $472 - $141.60 = $330.40, which is the sale price Gordon paid. Choice A, $141.60, is incorrect as it represents only the discount amount, not the final sale price. Choices B and C are also incorrect as they do not account for the correct calculations of the discount and final sale price.

Correct Answer: A

Rationale: The correct inequality is 30c + 5p ≤ 100. This represents the combinations of ink cartridges (c) and printer paper (p) that Tom may purchase, ensuring the total cost is less than or equal to $100. Choice B is incorrect because the total cost should be less than or equal to $100, not equal to. Choices C and D are also incorrect as they indicate the total cost being greater than $100, which is not the case given Tom's budget limit.

Correct Answer: A

Rationale: To simplify the expression 5 x 3 · 9 x 4, first perform the multiplications and divisions from left to right: 5 x 3 = 15 and 9 x 4 = 36. So, the expression becomes 15 · 36. When dividing fractions, multiply the first fraction by the reciprocal of the second fraction. Hence, 15 · 36 = 15/36. To simplify the fraction further, find the greatest common divisor, which is 3. Divide both the numerator and denominator by 3 to get the final result: 15/36 = 5/12. Therefore, the correct answer is A. Choices B, C, and D are incorrect because they do not represent the correct simplification of the given expression.

Correct Answer: C

Rationale: The range in the number of houses sold per year is calculated by subtracting the minimum number of houses sold from the maximum number of houses sold. In this case, the range is 42 (maximum) - 11 (minimum) = 31, not 29 as stated in the original rationale. Therefore, choice C (29) is incorrect. Choices A (20), B (25), and D (35) are also incorrect as they do not reflect the correct range of houses sold per year, which is 31.

Correct Answer: B

Rationale: Start by solving the multiplication and parentheses. The answer is -20.