Question

The parking lot of a college campus has 200 lamp posts. Each lamp post has two 1200-watt light bulbs. The lights are on an average of 10 hours per night year-round. Calculate the annual electric cost for the lights if the college pays 8.5 cents per KWHR.

Answer 1

Power:

$$P=(200)(2)(1200)=480000W=480kW$$

Time:

$$t=365(24)=8760 hr$$

Energy:

$$E=Pt=480(8760)=4204800kWhr$$

The annual electric cost for the lights:

$$C=(0.085)(4204800)=\$357408$$