Question

Three cubes of iron whose edges are 3 cm, 4 cm and 5 cm respectively are melted and formed into a single cube. The edge of the new cube formed is 
1. 4 cm
2. 6 cm
3. 8 cm
4. 10 cm

Answer 1

Correct Answer - Option 2 : 6 cm

Calculation:

Let the edge of the new cube be a.

Volume of a new cube = sum of volume of melted cubes

⇒ a³ = 3³ + 4³ + 5³

⇒ a³ = 27 + 64 + 125

⇒ a³ = 216 cm³

⇒ a = 6 cm

∴ The edge of the new cube formed is 6 cm.