Air conditioners are rated by BTUs. You learned about BTUs in Section 7-2, Example 6. One watt-hour is equivalent to 3.413 BTUs per hour. a. How many BTUs per hour are equivalent to a kilowatt-hour? b. If an air conditioner is rated at 16,000 BTUs per hour, how many watts does it require? Round to the nearest 100 watts. c. Express your answer to part b in kilowatt-hours. d. If you run an air conditioner for 18 hours per day for 31 days in July, how many kilowatt-hours will it require for the month? Round to the nearest 100 kilowatt-hours. e. Based on your answer to part d, and a rate of $0.13 per kilowatt-hour, estimate the cost of running the air conditioner for July to the nearest ten dollars.