A two-stage air compressor takes in 22.5 kg of air per minute at 15 °C and 1 bar and delivers it at 16.5 bar. At the intermediate pressure the air is cooled to the initial temperature. Assuming no clearance and pV^{1.2} = constant, determine (a) the intermediate pressure for least work (bar), (b) the heat rejected in the intercooler (kJ/min) and (c) the minimum power required (kW). Take c_{p} = 1 kJ/kg·K and R = 287 J/kg·K.