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≤2,400 and x+y≤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.