SOLUTION: If the basic charge for electricity is $0.0683/kWh, how much will it cost per year to run a 60W porch light, 8 hrs/day, everyday? Please show all work. Thank you. It gets tricky

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Question 84063: If the basic charge for electricity is $0.0683/kWh, how much will it cost per year to run a 60W porch light, 8 hrs/day, everyday? Please show all work. Thank you. It gets tricky somewhere bteween Joules (J) and kilowatt hours (kWh). Is this even an algebra problem or should I be asking the science tutors?
Answer by bucky(2189) (Show Source):
You can put this solution on YOUR website!
You don't have to get involved with joules or units other than those mentioned in the problem.
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Look at the problem this way. In one hour the bulb consumes 60 watts times 1 hour which
is the same as 60 watt*hours. To convert this to kw*hours, just divide by 1000. When you
do this division you get:
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60 w*hr/1000 w/kw = 0.060 kw*hr
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Units check:
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So for each hour it runs, the bulb uses up 0.060 kw*hr of energy.
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How many hours does the bulb run per year? At 8 hours per day for 365 days in the year, the
bulb runs 8 times 365 hours which is 2920 hours.
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Units check:
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Then in a year the total consumption is 0.060 kw*hr for each hour times the 2920 hours in
a year for an annual amount of:
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kw*hr per year.
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Units check:
.

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And at a cost of $0.0683 for each kw*hr the annual cost to run the bulb will be:
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$0.0683 * 175.2 = $11.96616 which rounds to $11.97.
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Units check - using D to represent dollars):
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Everything checks. Hope this helps you to see your way through this problem.