Three cubes whose edges measure 3 cm, 4 cm, and 5 cm respectively are melted to form a new cube. Find the surface area of the new cube formed.
Given,
Edge of three cubes are respectively = 3cm , 4 cm , 5 cm
So,
Sum of volume of these cubes = 
After melted these cubes a new cube is formed.
Let edge length of this new cube = a cm
So,
= 
=
Edge of new cube = 6 cm
Surface area of new cube = 
13