Question

A hemispheric tank filled with water is made empty by a pipe at the rate of 5 litre per second if diameter of tank is 3.5 m, then how much time will be taken to make the yank half empty?

Answer 1

Radius=3/2 m

volume of hemisphere=2/3 πr³

=2/3 * 22/7 * (3/2)³ =99/14 m³

vol. of water that would be emptied=1/2 of vol.of hemispherical tank

=1/2 *99/14 =99/28 m³

vol.=99/28 m³ *1000 litres

=99000/28 litres

in 1 second as 25/7 litres of water would be emptied

so,99000/28 litres of water would be emptied in =99000/28 *7/25

=3960/4

=990 seconds
Hope it helps.....