Steam enters the first stage of a turbine at 100 bars, 500°C and expands isentropically to 10 bars. It is then reheated to 500°C and expanded in the second stage to the condenser pressure of 0.1 bars. Steam is bled from the first stage at 20 bars and fed to a closed feed water heater. Feed water leaves the closed heater at 100 bars, 200°C (enthalpy = 856.8 kJ/kg) while the condensate exits as saturated liquid at 20 bars. This condensate is supplied to the open heater into which steam is bled at 4 bars pressure. Saturated liquid at 4 bars exits from the open heater and enters the closed heater. The condensate from condenser enters the open heater. The net output of the turbine is 50 MW. Assuming the turbine and pump processes to be isentropic. Determine the mass of steam bled at each feed water heater per kg of steam entering the first stage, the mass of steam entering the first stage per second, and the thermal efficiency.