a 2.5-m high 120-m2 house is maintained at 24c by an air-conditioning system whose COP is 2.9 . it is estimated that the kitchen, bath, and other ventilating fans of the house discharge a houseful of conditioned air once every hour . if the density of air is 1.20 kg/m3 , the unit cost of electricity is 0.18 / kwh and the amount of money " vented out" by the fans in 8 hours is 0.75 , determine the outdoor temperature