A rectangular prism has 6 faces. The area of each is given by length * width.
The area of the top and bottom is given by 25(4) = 100 sq. in. The area of the front and back is given by 25(8) = 200 sq. in. The area of the right and left is given by 4(8) = 32.
There are only 2 faces that have an area that is not a multiple of 100; 2/6 = 1/3.
