The cooling coil of a small air-conditioning system is to be designed for a heat-transfer rate of 48,000 Btu/hr from air at 14.7 psia and 90ºF, which flows steadily at a rate of 1500 ft3/min. The cooling coil is a finned-tube heat exchanger. The air flows over the finned surfaces, and heat transfer from the air causes the refrigerant inside the tubes to evaporate. R-410a flows inside the tubes and evaporates at a constant pressure of 40 psia from saturated liquid conditions to an exit temperature of 40ºF. Calculate the mass flow rate of liquid required and the exit temperature of the air.