Aswimming pool has has to be drained for maintenance the pool shaped like a cylinder with a diameter of 8 meters and a depth of 1.5 m suppose water is pumped out of the pool at a rate of 12 m cubed per hour if the pool starts completely full how many hours will it take that to the pool use 3.14 for pi

D = diameter = 8
r = radius = d/2 = 8/2 = 4
h = height = 1.5

V = volume of cylinder pool
V = pi*r^2*h
V = 3.14*4^2*1.5
V = 75.36

"Water is pumped out at a rate of 12 m^3 per hour", so this means
1 hr ---> 12*1 = 12 m^3 of water is pumped out
2 hr ---> 12*2 = 24 m^3 of water is pumped out
3 hr ---> 12*3 = 36 m^3 of water is pumped out
... and so on...
x hr ---> 12*x of water is pumped out

We want to pump out 75.36 cubic meters of water. So set 12x equal to 75.36 and solve for x

12x = 75.36
12x/12 = 75.36/12
x = 6.28

It will take a little over 6 hours to drain the pool

note1: 6.28 hrs = 6 hrs, 16 minutes, 48 seconds

note2: The value 6.28 is approximate because the approximation pi = 3.14 was used