3. An air-conditioner is removing heat from a room at 20°C at a rate of 9000 kJ/h and rejecting the waste heat to the outdoors at 35°C. If the coefficient of performance of the air-conditioner is 3, the power consumed by the air-conditioner is: (a) 0.10 kW (b) 0.67 kW (c) 1.5 kW (d) 2.0 kW (e) 6.0 kW