First find the volume of the large rectangular prism:

$\displaystyle{V}={l}\cdot{w}\cdot{h}={20}\cdot{5}\cdot{5}={500}\usepackage{cmbright}\Huge\$

Then find the volume of the hole, shaped like a rectangular prism:

$\displaystyle{V}={20}\cdot{2}\cdot{2}={80}\usepackage{cmbright}\Huge\$

Subtract the volume of the hole from the volume of the large rectangular prism: $\displaystyle{500}-{80}={420}\usepackage{cmbright}\Huge\$

The volume of the solid is 420 cubic centimeters.