Question

vals whole-house central air conditioner uses 3,000 watts when running. val runs the ac 4 hours per summer day. electricity costs (15 cents)/(1 kilowatt-hour). how much does vals ac cost to run for a summer month of 30 days?

Explanation:

Step1: Convert watts to kilowatts

The AC uses 3000 watts. Since 1 kilowatt = 1000 watts, we divide by 1000: $3000 \div 1000 = 3$ kilowatts.

Step2: Calculate daily energy usage (in kilowatt - hours)

The AC runs for 4 hours per day. Energy (in kilowatt - hours) is power (in kilowatts) times time (in hours). So, $3 \text{ kW} \times 4 \text{ hours} = 12$ kilowatt - hours per day.

Step3: Calculate monthly energy usage (in kilowatt - hours)

There are 30 days in a summer month. So, $12 \text{ kWh/day} \times 30 \text{ days} = 360$ kilowatt - hours per month.

Step4: Calculate monthly cost (in cents)

Electricity costs 15 cents per kilowatt - hour. So, $360 \text{ kWh} \times 15 \text{ cents/kWh} = 5400$ cents.

Answer:

5400