The hallways of a 3-story building in denver, colorado use 8000 lights per floor and each light is an incandescent bulb rated at 50 w. a). estimate the amount of energy that could be saved in august by turning the lights on when the sun sets, and turning them off when it becomes light (you can the daylight b). assuming that the power for the lights comes from a 30% efficient coal-fired power plant, estimate the amount of co2 that would be saved with this conservation measure. assume that the chemical composition of the coal is ch0.8 and that coal has a heating value of 29 mj/kg.