Question

A cylindrical rod whose height is $8$ times its radius is melted and cast into spherical balls of the same radius. The total number of spherical balls so formed is

• A. $3$
• B. $4$
• C. $6$
• D. $8$

Answer 1

Answer: (C)

$6$

Volume of cylindrical rod $=\pi r^2.8r=8\pi r^3$
Volume of sphere$=\frac{4}{3}\pi r^3$
$\therefore$ Number of spheres $=\frac{8\pi r^3}{\frac{4}{3}\pi r^3}=6$