
Use the graph to estimate the electricity consumption of the United States. Round your answer so it is reasonable for the context. (See Example 1.)

From the graph, you can estimate that the consumption of electricity in the United States (in 2008) was about 3900 billion kilowatt hours.
3,900,000,000,000 kilowatt hours
Download the spreadsheet of data to determine the actual amount of electricity consumed by the United States in 2008. Was your estimate close?
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Estimate the total electricity consumption of Japan, Russia, India, and Canada. Is it greater than or less than the electricity consumption of the United States? (See Example 1.)
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In 2008, the population of the United States was about 304 million. Use the graph to estimate the amount of electricity consumed per person. Round your answer so it is reasonable for the context. (See Example 1.)

To estimate the electricity consumption per person, divide the consumption by the population.
In 2008, the U.S. electricity consumption was about 13,000 kilowatthours per person.
Calculator Hint:
When entering numbers like these into a calculator, you can save keystrokes by dividing out the same number of zeros from the numerator and denominator.
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In 2008, the population of Canada was about 33 million. Estimate the amount of electricity consumed per person. Which country consumed more electricity per person, Canada or the United States? (See Example 1.)
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When posting a comment, you agree to our Terms of Use.Showing 2 commentsGuest 2 years ago guest0 0Guest 2 years ago NARYM0 0 
Two refrigerator models and their annual electricity consumptions are shown. Assume the price of electricity is $0.1202 per kilowatthour (kWh). (See Example 2.)
 Estimate the annual electricity cost of each model.
 How much money will you save in electric bills each year if you buy the topfreezer model instead of the sidebyside model?


To estimate the annual electricity cost, multiply the usage by the cost.
 You will save about 76  64 = $12 a year in electric bills.

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Two refrigerator models and their annual electricity consumptions are shown. Assume the price of electricity is $0.1202 per kilowatthour (kWh). A topfreezer model with an ice dispenser consumes 90 kilowatthours per year more than the standard topfreezer model. (See Example 2.)
 Estimate the annual electricity cost of the topfreezer model with the ice dispenser.
 How much does the ice dispenser add to the annual electricity cost of the topfreezer model?
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Two refrigerator models and their annual electricity consumptions are shown. Assume the price of electricity is $0.1202 per kilowatthour (kWh). Your current refrigerator consumes 700 kilowatthours per year and should last about 7 more years. (See Example 2.)
 How much will your current refrigerator cost you over the next 7 years?
 How much would the topfreezer model cost you over the same time period?
 You buy the topfreezer model for $549.99. Will the difference in electricity costs over the next 7 years cover the price of the new refrigerator? Explain.

 Your current refrigertor will cost about
This is about over the next 7 years. 
From Exercise 5, the topfreezer model would cost about
over the next 7 years.

The difference in the costs of electricity during the 7 years is only about $140. By itself, this does not justify getting rid of your current refrigerator and buying a more efficient model. On the other hand, when your current refrigerator quits working in 7 years, it would be good to consider buying the more "planet friendly" model.
 Your current refrigertor will cost about
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Two refrigerator models and their annual electricity consumptions are shown. Assume the price of electricity is $0.1202 per kilowatthour (kWh). You own the topfreezer model. Suppose the price of electricity decreases to $0.12 per kilowatthour. How much will you save in electric bills each year? (See Example 2.)
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