Air enters the compressor of a gas-turbine engine at 300K and 100 kPa, where it is compressed to 700 kPa and 580K. Heat is transferred to air in the amount of 950 kJ/kg before it enters the turbine. For a turbine isentropic efficiency of 86 percent, determine (a) the fraction of the turbine work output used to drive the compressor and (b) the thermal efficiency. Assume constant specific heats at room temperature