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 3m in diameter?

Answer 1

Volume of hemispeherical tank, `V = 2/3pir^3`
Here, diameter,`d= 3m`
So, radius, `r = 1.5m`
So, `V = 2/3**22/7**(1.5)^3 = 2/3**22/7**27/8=99/14`
`V/2 = 99/28`
Let `t` is the time taken in seconds to empty half of the tank,
As, the tank is emptied at the rate of `25/7` litres per second. then,
`25/7**t = 99**1000/28`(Multiplied by 1000 to convert it into litres)
`=>t = 99000/28**7/25 = 990 ` seconds` = 990/60 = 16.5` minutes