Three cubes of metal with edges 3 cm, 4 cm and 5 cm respectively are melted to form a single cube. The lateral surface area of the new cube formed is
Here, the volume of three cubes = volume of the new cube
Volume of a cube = (side)3
Volume of three cubes = (3)3 + (4)3 + (5)3= (27 +64+ 125) cm3 =216 cm3
⇒ Volume of new cube = 216 cm3= (side)3
⇒ (side)3 = (6 cm)3
⇒ side = 6cm
Lateral surface area = 4(side)2 = 4(6)2 = 144cm2