A rectangular block of candy 10 inches by 10 inches by 5 inches is coated on all faces with a very thin layer of chocolate. The block of candy is then cut into cubes measuring 1 inch by 1 inch by 1 inch. What percent of the cubes have no chocolate on them?
The rectangular block 10 inches by 10 inches by 5 inches is cut into cubes, 1 inch per side.
This block has 10 x 10 x 5 = 500 of these 1 inch cubes.
Every block on the outside inch has some chocolate. Only those completely in the inside
do not. The inside consists of a block 8 inches by 8 inches by 3 inches.
There will be 8 x 8 x 3 = 192 blocks that have no chocolate.
The percentage is: 192 / 500 = 0.384 or 38.4%.