Choice A is correct. It’s given that the truck can tow a trailer if the combined weight of the trailer and the boxes it contains is no more than pounds. If the trailer has a weight of pounds and each box weighs pounds, the expression , where is the number of boxes, gives the combined weight of the trailer and the boxes. Since the combined weight must be no more than pounds, the possible numbers of boxes the truck can tow are given by the inequality . Subtracting from both sides of this inequality yields . Dividing both sides of this inequality by yields , or is less than or equal to approximately . Since the number of boxes, , must be a whole number, the maximum number of boxes the truck can tow is the greatest whole number less than , which is .
Choice B is incorrect. Towing the trailer and boxes would yield a combined weight of pounds, which is greater than pounds.
Choice C is incorrect. Towing the trailer and boxes would yield a combined weight of pounds, which is greater than pounds.
Choice D is incorrect. Towing the trailer and boxes would yield a combined weight of pounds, which is greater than pounds.