Water is pumped from a lake to a storage tank 20 m above at a rate of 70 L/s while consumi...

Water is pumped from a lake to a storage tank 20 m above at a rate of 70 L/s while consuming 20.4 kW of electric power. Disregarding any frictional losses in the pipes and any changes in kinetic energy, determine (a)the overall efficiency of the pump-motor unit and (b)the pressure difference between the inlet and the exit of the pump.