Answer:
Part A: 13440 cubic inches.
Part B: A - 2940 cubic inches.
Explanation:
The volume of the box = 24x20x28 = 13440 cubic inches.
The problem tells us that his gift is 10,500 cubic inches. So subtract that from the volume of the box.
13440-10500 = 2940 cubic inches. The answer is A.