#### Question

A vessel is in the form of an inverted cone. Its height is 8 cm and the radius of its top, which is open, is 5 cm. It is filled with water up to the brim. When lead shots, each of which is a sphere of radius 0.5 cm are dropped into the vessel, one-fourth of the water flows out. Find the number of lead shots dropped in the vessel.

#### Solution

Height (*h*) of conical vessel = 8 cm

Radius (*r*_{1}) of conical vessel = 5 cm

Radius (*r*_{2}) of lead shots = 0.5 cm

Let *n* number of lead shots were dropped in the vessel.

Volume of water spilled = Volume of dropped lead shots

`1/4 xx "Volume of cone" = n xx 4/3 r_2^3`

`1/4xx1/3pir_1^2h = n xx 4/3pir_2^3`

`r_1^2h = n xx 16r_2^3`

`5^2xx8 = nxx 16xx (0.5)^3`

`n = (25xx8)/(16xx(1/2)^3) = 100`

Hence, the number of lead shots dropped in the vessel is 100.