A cylindrical rod whose height is 8 times of its radius is melted and recast into spherical balls of same radius. The number of balls will be

Volume of a sphere = (4/3)πr^{3}

Volume of a cylinder = πr^{2}h

Given, cylindrical rod whose height is 8 times of its radius is melted and recast into spherical balls of same radius.

Let the number of such balls be ‘a’.

⇒ π × r^{2} × 8r = a × (4/3)π × r^{3}

⇒ a = 6

6