Hydro-electric power is to be generated by installing a hydraulic turbine-generator combination 110 m below the free surface of a reservoir that supplies water at a steady rate of 900 kg/s. Assuming frictional energy losses in the piping to be negligible, if the mechanical power output of the turbine is 800 kW and the electrical power output is 750 kW, calculate: a. efficiency of the turbine b. efficiency of the combined turbine-generator system