Question

A cylindrical tub of radius 16 cm contains water to the depth of 30 cm. A spherical iron ball is dropped into the tub, As a result the level of water rises by 9 cm. The radius of the ball is

• A. 10 cm
• B. 6 cm
• C. 12 cm
• D. None of the above

Answer 1

The correct option is C 12 cm

Volume of sphere = Volume of cylindrical ABCD
$\frac{4}{3}\pi r^3=\pi R^{2}h$
$\Rightarrow \frac{4}{3}{r}^3=16\times 16\times 9$
$\Rightarrow r^3=16\times 16\times 9\times \frac{3}{4}=1728={12}^3$
r = 12