# How much metal is needed to cast a cubical metal box with outer side 10 inches long if the thickness of its walls should be exactly 2 inches?

##### 1 Answer

It would take

#### Explanation:

Find the volume of the box if the box was solid:

If the side of the cube is 10 inches, and the width of the walls is 2 inches, then the width of the cube of air inside of the box is

The volume of that box is

Thus, the amount of metal to cast the box is