Question

The edges of three cubes of metal are $3$ cm, $4$ cm and $5$ cm. They are melted and formed in to a single cube. Find the edge of the new cube.

• A. $6$ cm
• B. $5$ cm
• C. $4$ cm
• D. $8$ cm

Answer 1

The correct option is A $6$ cm

Volume of cubes $=3^3+4^3+5^3=27+64+125=216$

Volume of new cube $=$ edge${}^3=216=6^3$

$\therefore$ edge $=6$ cm