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A washing machine uses 1.8 × 105 watts of power. If it is in use for 2 hours per day (on average), how many kilowatt hours will it use in 30 days? A. 1.1 × 104 kilowatt hours B. 36 kilowatt hours C. 18 kilowatt hours D. 540 kilowatt hours E. 1.1 × 106 kilowatt hours

Answer :

skyluke89

Answer:

A. 1.1 × 104 kilowatt hours

Explanation:

Here the power used by the washing machine is

[tex]P=1.8\cdot 10^5 W[/tex]

where power is the rate at which energy is consumed.

This power can be rewritten as

[tex]P=1.8\cdot 10^2 kW=180 kW[/tex]

We also know that the washing machine is used for a time of

t = 2 hours

every day for 30 days, so the total time the machine has been used is

[tex]t=2\cdot 30 = 60h[/tex]

Therefore, the number of kilowatt hours the washing machine has consumed is:

[tex]E=Pt=(180 kW)(60 h)=10800 kWh\sim 1.1\cdot 10^4 kWh[/tex]

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