Question

If 3pumps can empty a cistern in 2days by working 8hours a day ,then how many hours day must 4 pumps work to empty a cistern in one day?

Answer 1

no. of pumps. hours
3. 8×2=16
4. x hours

inversely proportional......
so


3×16. = 4×x
3×4=x

x=12 hours




hope this helps.....