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 empty half the tank, if it is 3 m in diameter?

Answer 1

Answer:

16.5 minutes

Step-by-step explanation:

Given,Diameter of base of tank = 3 m.

Then, radius = (3/2) m.

We know that volume of hemispherical tank = (2/3) πr³

= (2/3) * (22/7) * (3/2)³

⇒ (99/14) m³.

Now,

Volume of half tank = (1/2) * volume of tank

                                 = (1/2) * 99/14

                                 = (99000/28) litres.

As, the rate of water emptied by the pipe = 25/7 litres.

So, the time taken to empty half the tank = (99000/28) * (7/25)

=  693000/700

= 990 seconds

= (990/60) minutes

= 16.5 minutes

= 16 minutes 30 seconds.

Hope it helps!