In a hypothetical cyclic steam power plant incorporating a single direct-contact feedwater heater, the steam leaves the boiler at 1 MPa and 400 C and the condenser pressure is 4 kPa. Expansion in the turbine is reversible and adiabatic. The feedwater heater takes steam bled from the turbine at pressure of 75 kPa and heats the feedwater to the corresponding saturation temperature. Temperature and enthalpy changes of the fluid in passing through any pumps may be neglected. Calculate: a. The mass of steam bled from the turbine per kg of steam leaving the boiler. b. The cycle efficiency. c. The improvement in thermal efficiency due to the introduction of this single stage of feed heating, expressed as a percentage of the Rankine cycle efficiency.