Question

Three cubes of metal whose edges are 3 cm, 4 cm and 5 cm respectively are melted and recast into a single cube. Find the edge of this new cube.

Answer 1

Let x be the edge of new cube, then

According to problem

volume of the new cube = sum of the volume of three cubes

⇒ x³ = (3)³ + (4)³ + (5)³

⇒ x³ = 27 + 64 + 125

⇒ x³ = 216

⇒ x = 6 cm

Hence, edge of the new cube is 6 cm long.