Question

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

Answer 1

v = 4/3 pi r^3, so the tank can hold

1/2 * 4/3 * pi * (3/2)^3 = 7.07 m^3 of water

So, it will take

7.07 m^3 / (25/7 L/s) to drain

I'll let you do the conversion from m^3 to liters.

Answer 2

16.5minutes

Answer 3

Given, diameter = 3m
So radius = 3/2 m
Rate at which air is pumped is 25/7 liter per second
Volume of tank = 2/3 πr^3 = 99/14m^3
=99000/14 liters

Since 1 liter of air can be pumped in 7/25 sec

Therefore , 99000/14 liter of air can be pumped in 7/25×99000/14 sec

= 1980 sec
= 33 min