Question

Three cubes whose edges are $3cm,4cmand5cm$ respectively are melted to form a single cube. Find the volume of the new cube.

• A. $210c{m}^3$
• B. $213c{m}^3$
• C. $224c{m}^3$
• D. $216c{m}^3$

Answer 1

The correct option is D $216c{m}^3$

Given:
Side of cube 1, $V_1=3cm$,
Side of cube 2, $V_2=4cm$,
Side of cube 3, $V_3=5cm$.

Volume of new cube is the sum of volume of the three cubes.

Let $V$ be the volume of the new cube.

Volume of a cube is equal to the cube of its side.
$V=V_1+V_2+V_3$
$V=3^3+4^3+5^{3}c{m}^3$
$V=216c{m}^3$