Question

A hemispherical tank full of water is emptied by a pipe at the rate of 25/7 litres per second. How much time will it take to empty half the tank,if it is 3 m in diameter

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

Answer 2

Answer:

989 seconds

Step-by-step explanation:

Radius =1.5m

Volume of the tank = (2/3)πr³

=(2/3)(3.14)(1.5)³

=7.065m³

=7065 L

Time taken to half the tank at the rate of 25/7 L/s

=(1/2)(7065)(25/7)

=989 seconds