Question

Find the volume of the following figure, if volume of each inside cube is 1 cubic unit.

• A. 24 cubic units
• B. 18 cubic units
• C. 20 cubic units
• D. 36 cubic units

Answer 1

The correct option is C 20 cubic units

We can find the volume of the above figure by dividing the composite figure into unit cubes and adding the volumes.

The above composite figure can be divided into two smaller cubes - one small one on the top and the other on the bottom.

The bigger cube on the bottom has 6 cubes each in 3 layers.

Volume of 1 cube = 1 cubic unit.

So, the volume of the bigger cube is
$=6\times 3\times 1=18\text{cubic units}$

The small cube on the top has two unit cubes.

So, their volume will be
$=2\times 1=2\text{cubic units}$

∴ The volume of the figure is
$=18+2=20\text{cubic units}$