A 100-W driveway light bulb is on 10 hours per day.If the power company charges 10¢ for each kilowatt-hour of electric energy used,estimate the yearly cost to operate the bulb if it is used every day for a 365-day year.
A)$3.65
B)$7.30
C)$37
D)$73

Question

Quizplus · Accepted Answer

First, we need to convert the wattage of the light bulb to kilowatts, which is 0.1 kW (100 W ÷ 1000). 
Then, we can calculate the daily energy usage in kilowatt-hours (kWh) by multiplying the power (0.1 kW) by the number of hours per day (10 hours/day): 
0.1 kW x 10 hours/day = 1 kWh/day 
Finally, to calculate the yearly cost, we multiply the daily energy usage by the cost per kWh and by the number of days in a year: 
1 kWh/day x $0.10/kWh x 365 days/year = $36.5 ≈ $37 
Therefore, the best choice is C.

A 100-W Driveway Light Bulb Is on 10 Hours Per