A small conference room that can hold 60 people is to be air-conditioned with window airconditioning units of 6 horsepower (hp) cooling capacity. A person at rest may be assumed to dissipate heat at a rate of about 340 Btu/h. There are 15 light bulbs in the room, each with the power of 340 Btu/h. The rate of heat transfer to the classroom through the walls and the windows is estimated to be 14,000 Btu/h. If the room air is to be maintained at a constant temperature of 70oF, determine the number of window air-conditioning units required