To find the volume of the box you will use the diameter and height of the can to determine the minimum length, width, and height of the box.
If the number of cans in each layer is 4 cans by 5 cans, then you will multiply each by 3 inches to find the necessary length and width.
4 x 3 = 12 inches
5 x 3 = 15 inches
There are 2 layers, so 7 x 2 = 14 inches.
12 x 15 x 14 = 2520 cubic in.