SAT Mathematics Practice Test 2

Since x is the number of $40-$pound boxes, $40x$ is the total weight, in pounds, of the $40-$pound boxes; and since y is the number of 65-pound boxes, $65y$ is the total weight, in pounds, of the $65-$pound boxes. The combined weight of the boxes is therefore $40x+65y,$ and the total number of boxes is x + y. Since the forklift can carry up to 45 boxes or up to 2,400 pounds, the inequalities that represent these relationships are $40x+65y\leq 2,400$ and $x+y \leq 45$.Choice B is incorrect. The second inequality correctly represents the maximum number of boxes on the forklift, but the first inequality divides, rather than multiplies, the number of boxes by their respective weights. Choice C is incorrect. The combined weight of the boxes,$40x+65y$, must be less than or equal to $2,400$ pounds, not 45; the total number of boxes,$x + y$, must be less than or equal to $45$, not $2,400$.Choice D is incorrect. The second inequality correctly represents the maximum weight, in pounds, of the boxes on the forklift, but the total number of boxes, $x+y,$must be less than or equal to $45$,not $2,400.$