Correct Answer: D

Rationale: The mean number of vacuum cleaners sold per month is 31.7, the mode is 29, the median is 31, and the range is 29. The mode being equal to the range is the correct statement. Option A is incorrect because the mean (31.7) is greater than the median (31). Option B is incorrect as the mode (29) is not greater than the median (31). Option C is incorrect since the mode (29) is not less than the mean, median, or range.

Correct Answer: D

Rationale: To divide fractions, you multiply the first fraction by the reciprocal of the second fraction. In this case, (2/7) · (5/6) becomes (2/7) (6/5) = 12/35. Therefore, the correct answer is 12/35. Choice A (2/5), choice B (35/15), and choice C (5/21) are incorrect because they do not correctly simplify the given expression.

Correct Answer: A

Rationale: The correct expression for Jonathan's monthly bill is 65 + 0.12x, where x represents the number of roaming minutes. The $65 monthly flat rate is added to the product of $0.12 per minute and the number of roaming minutes (x). Choice B is incorrect because it incorrectly multiplies the flat rate by x and adds the per-minute charge. Choice C is incorrect as it combines the flat rate and the per-minute charge into a single value. Choice D is incorrect as it incorrectly multiplies the flat rate by x and adds the per-minute charge separately.

Correct Answer: A

Rationale: To find the volume of the aquarium, we multiply its length, width, and height. The formula for the volume of a rectangular solid is V = l w h. Substituting the given dimensions, we get V = 30 10 12 = 3600 cubic inches. Therefore, the aquarium can hold 3600 cubic inches of water. Choice B (52 cubic inches), Choice C (312 cubic inches), and Choice D (1144 cubic inches) are incorrect as they do not correctly calculate the volume of the aquarium based on its dimensions.

Correct Answer: C

Rationale: Erma receives a 25% discount on the $44 sweater, which amounts to a $11 discount. Therefore, she pays $44 - $11 = $33 for this sweater. Adding this discounted price to the $50 sweater, Erma will spend a total of $50 + $33 = $83. Choice A, $79, is incorrect because it does not include the correct calculation for the discounted sweater. Choice B, $81, is incorrect as it does not consider the discounts on both sweaters. Choice D, $85, is incorrect since it overestimates the total amount Erma will spend.