After leaving the condenser of a power station, water enters the top of a cooling tower as a spray and falls over baffles to the bottom where it is recirculated to the power plant. at the time air enters the bottom of the tower, is sucked up by a fan, and billows out of the top generating huge white clouds. the water enters the tower at 35℃ and 120 ݇݃kg/s and is cooled to 25℃ by the air that enters at 20℃, 50 % relative humidity, and atmospheric pressure. if the air leaves saturated at 30℃, calculate the required flow rate of air.