Question

The PA system at North High School requires 400 watts when it is switched on. How much would it cost to run it for 3 hours, at a cost of $0.10 per kilowatt-hour?

Answer 1

$0.12

Explanation:

0.4 kW for 3 hours is (0.4 kW)(3 H) = 1.2 kWh.

At $0.10 per kWh, the cost is ...

(1.2 kWh)×($0.10/kWh) = $0.12

It costs 12 cents to run the amplifier for 3 hours.