Question

A hemispherical tank of radius 1 3/4 m. is full of water. A pipe connected to it empties it at the rate of 7 litres per second. How much time will it take to empty the tank?

Answer 1

volume of hemispherical body=2/3 πr^3
=2/3 x 22/7 x (7/4)^3
=11.225 m^3
hence
volume of spherical body =11225 L
now,
time =volume/rate
=11225/7 =1603.58 sec

approximately time =1604 sec

Answer 2

Radius = 1 3/4 = 7 / 4 m
Volume = 2/3 πr³
= 2 / 3 × 22 / 7 × (7 / 4)³
= 2 / 3 × 22 / 7 × 343 / 64
= 11.2291667 m ³
= 11229.1667 litres
Water that falls in 1 sec = 7 Litres.
Time taken to empty the tank with 11229.1667 litres of water = 11229.1667 litres ÷ 7
= 1604.16667 sec