The gas-turbine cycle of a combined gas-steam power plant has a pressure ratio of 8. Air enters the compressor at 290 K and the turbine at 1,400K. The combustion gases leaving the gas turbine are used to heat the steam at 15 MPa to ,450°C in a heat exchanger. The combustion gases leave the heat exchanger at 247°C. Steam expands in a high-pressure turbine to a pressure of 3MPa and is reheated in the combustion chamber to 500oC before it expands in a low-pressure turbine to 10 kPa. The mass flow rate of steam is 30 kg/s. Assuming all the compression and expansion processes to be isentropic, determine (a) the mass flow rate of air in the gas-turbine cycle, (6) the rate of total heat input, and (0 the thermal efficiency of the combined cycle.