Two 100-w light bulbs used a total of 400wh of energy. For how many hours did the light bulbs use power?

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01-01-2015
Mathematics

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Two 100-w light bulbs used a total of 400wh of energy. For how many hours did the light bulbs use power?

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apologiabiology apologiabiology · Answer 1 · 2015-01-01T08:28:23+01:00

apologiabiology apologiabiology

01-01-2015

I'm assuming that you meant to write 'two 100-w per hour light bulbs used a total of 400w. how many hours did the bulbs run'

so each used 100w per hour and there are 2 light bulbs so in 1 hour 200w is used
200wh times x hour=200wx=400w
divide both sides by 200w
x=2
they ran for 2 hours

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