A 21-inch TV set is rated at 75W. The TV is used an average of 31/2 h each day for a week. How many kilowatt-hours of energy are used during the week? Round your answer to the nearest tenth.

Question

Quizplus · Accepted Answer

First, we need to convert the time used into hours: 
31/2 h/day x 7 days = 24.5 hours in a week 
Next, we can calculate the energy used: 
75W x 24.5 hours = 1837.5 Wh 
To convert to kilowatt-hours, we divide by 1000: 
1837.5 Wh ÷ 1000 = 1.8375 kWh 
Rounding to the nearest tenth gives us an answer of 1.8 kWh, which is choice C.

A 21-Inch TV Set Is Rated at 75W