Question

a family of four lives in a three - bedroom house and uses an average of 900 kwh of electricity per month. the family cools their house for three months during the summer with two window - unit air conditioners that each use 350 kwh of electricity per month. which of the following is the percentage of the familys total annual electricity that is used to run the two air conditioners for the three summer months?
a 9.7%
b 19.4%
c 38.8%
d 77.8%

Explanation:

Step1: Calculate annual electricity consumption

The family uses \(900\) kWh per month. Annual consumption \(=900\times12 = 10800\) kWh.

Step2: Calculate electricity consumption for air - conditioners

Each air - conditioner uses \(350\) kWh per month. Two air - conditioners per month: \(2\times350=700\) kWh. For three months: \(700\times3 = 2100\) kWh.

Step3: Calculate the percentage

Percentage \(=\frac{2100}{10800}\times100\%\)

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Answer:

B. \(19.4\%\)