12.27 A converging-diverging nozzle with a throat area of 2 in 2 is connected to a large tank in which air is kept at a pressure of 80 psia and a temperature of 60 F. If the nozzle is to operate at design conditions and the ambient pressure outside the nozzle is 12.9 psia, calculate the exit area of the nozzle and the mass flow rate. Assume the flow is isentropic.