Ametal ball with a radius of 6 cm is melted to form some small balls each with radius of 1.5 cm. find the number of small balls that can be formed.

Volume of a sphere = 4/3 * pi * r^3
Volume of big sphere = 4/3 *22/7*6*6*6
Volume of small sphere = 4/3*22/7*1.5*1.5*1.5

Therefore number of small balls = (Volume of big sphere)/(Volume of small sphere)
= (4/3*22/7*6*6*6)/(4/3*22/7*1.5*1.5*1.5) [4/3 & 22/7 get cancelled]

Therefore we are left with (6*6*6)/(1.5*1.5*1.5)
=4*4*4
=64

The answer is all about the number 4