SOLUTION: Commonwealth Edison Company's charge for electricity in January 2010 was 9.44 cents per kilowatt-hour. In addition, each monthly bill contains a customer charge of $12.55. If last

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Question 1208892: Commonwealth Edison Company's charge for electricity in January 2010 was 9.44 cents per kilowatt-hour. In addition, each monthly bill contains a customer charge of $12.55. If last year's bills ranged from a low of $76.27 to a high of $248.55, over what range did usage vary (in kilowatt-hours)?
Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

x = number of kilowatt-hours
0.0944x = cost in dollars of using that amount of electricity
0.0944x+12.55 = add on the fixed fee of $12.55

The cost is somewhere between $76.27 and $248.55
I'll assume that each endpoint is included.
76.27%3C=cost+%3C=+248.55

76.27%3C=0.0944x%2B12.55+%3C=+248.55

76.27-12.55%3C=0.0944x%2B12.55-12.55+%3C=+248.55-12.55 Subtract 12.55 from all sides.

63.72%3C=0.0944x+%3C=+236

63.72%2F0.0944%3C=0.0944x%2F0.0944+%3C=+236%2F0.0944 Divide all sides by 0.0944

675%3C=x+%3C=+2500

The usage of kilowatt-hours is somewhere between 675 and 2500.