How much does it cost to use a 24w radio for 3hours at 9cents per kilowatt-hour?

To calculate the cost of using a 24w radio for 3 hours at a rate of 9 cents per kilowatt-hour, we first need to convert the power consumption of the radio from watts to kilowatts.

24 watts = 0.024 kilowatts

Next, we calculate the total energy consumption in kilowatt-hours:

0.024 kilowatts x 3 hours = 0.072 kilowatt-hours

Finally, we calculate the total cost:

0.072 kilowatt-hours x $0.09 = $0.00648

Therefore, it would cost $0.00648 to use a 24w radio for 3 hours at a rate of 9 cents per kilowatt-hour.