Question

a 20 hp electric motor pumps water from a walk that is 10m deep into a water tank 3m above the ground level. how long does it take the pump to fill a 2000 L water tank.

Answer 1

you will take 20*10*3 so as to obtain the volume which will be 600 cubic metres.
since the volume together width depth are in different units u will Change cubic metres into litres by multiplying by a thousand which will give u 600000l.
600000divided by 600 you will get 1000