SOLUTION: If 500 kWh cost $57.61, and 1000 kWh cost $108.56, how much does does 713 kWh cost?

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: If 500 kWh cost $57.61, and 1000 kWh cost $108.56, how much does does 713 kWh cost?       Log On


   

Question 207812: If 500 kWh cost $57.61, and 1000 kWh cost $108.56, how much does does 713 kWh cost?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
If 500 kWh cost $57.61, and 1000 kWh cost $108.56, how much does does 713 kWh cost?
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You have two points relating kWh and cost: (500,57.61) and (1000,108.56)
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Assuming the relation is linear, find the linear equation:
slope = (108.56-57.61)/(1000-500) = 0.1019
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Intercept: 108.56 = 0.1019*1000 + b
b = 108.56- 101.90
b = 6.66
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Equation:
C(x) = 0.1019x + 6.66
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So C(713) = 0.1019*713 + 6.66 = $79.31
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Cheers,
Stan H.