The volume of a box is equal to the product its width, length and height
V = whl
Since all of the sides are 4 inches, we end up with
V= 4*4*4
Simplify to V = 16*4 = 64.
If the volume of one box is 64:
V = 64
The volume of 12 boxes is 64 * 12.
12V = 768
Since the volume of 12 boxes is the same as the volume of the carton, the volume of the carton must be 768 cubic inches.