A gas turbine set takes in air at \(27^{\circ} \mathrm{C}\) and \(1 \mathrm{~atm}\). The pressure ratio is 4 and the maximum temperature is \(560^{\circ} \mathrm{C}\). The compressor and turbine efficiencies are 0.83 and 0.85 respectively. Determine the overall efficiency of the set.