Steam enters an extraction turbine in a vapor power plant operating at steady stte at 10 MPa, 480 C. 25% of the steam is extracted from the turbine at 0.7MPa, 180 C where it is directed to a feedwater heater. The remaining steam expands to a pressure of 6 kPa and a quality of 0.92 where it is discharged to a condenser. Heat transfer from the turbine to the surroundings is neglible as are kinetic and potential energy effects. The turbine develops a power output of 20 MW. Determine the mass flow rate of steam entering the turbine in kg/h.