Question

The formula that relates the wattage of an appliance to the cost to run the appliance is 10000 where W is the wattage of appliance, C is the cost to use the appliance per month, t is the time in hours per month, and c is the cost of electricity per kilowatt hour. Use $0.15 per kilowatt-hour for the cost of electricity a. How much does it cost to run a 60-watt light bulb 720 hours a month? A.$0.15 C.$12.32 b. $6.48 D. $288

Answer 1

Given the formula that relates the wattage (W) of an appliance to the running cost(C) to be:

`W=(1000C)/(tc)`

where, t = time in hours per month

c = cost of electricity per kilowatt-hour

`if\text{ c = \$}0.15,\text{ }t=720\text{ hours },\text{ W}=60\text{watts, C=?}`

Using the relation, substitute the given values above in order to find C

`\begin{gathered} 60=(1000C)/(720*0.15) \\ 1000C=60*720*0.15 \\ 1000C=6480 \\ C=(6480)/(1000) \\ C=6.48 \\ \\ \text{Therefore, it costs \$6.48 (option b is the best answer choice)} \end{gathered}`