Electricity Usage
publish date: 2025/04/21 20:51:51.172008 UTC
volume_muteThe average U.S. household uses 10,656 kilowatt-hours of electricity each year. Several energy conservation groups would like each household to take steps to reduce its electricity usage by 5%. Estimate 5% of 10,656 kilowatt-hours.
(Source: U.S. Department of Energy)
Answer =
Correct Answer
Explanation
We will find 10% of 10,656.Then, we will divide an approximation of that result by 2. 5% of a number is one-half of 10% of a number.
Solution
First, we find 10% of 10,656.
- Move the understood decimal point in 10,656 one place to the left
- 10$ of 10,656 = 1,065.6
We will use 1,066 as an approximation of this result because it is close to 1,065.6 and because it is even, and, therefore, divisible by 2.Next,we divide the approximation by 2 to estimate 5% of 10,656.
$\frac{1,066}{2} = 533$
Theus 5% of 10,656 ≈ 533. A 5% reduction in electricity usage by the average U.S. household is about 533 kilowatt-hours.
Reference
Mathematics for college students