SOLUTION: The Morgans paid $50.40 for 1500 kilowatts hours of electricity one month and $50.80 for 1680 kwh the next month how much should they expect to pay for 1840 kwh?

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Question 762909: The Morgans paid $50.40 for 1500 kilowatts hours of electricity one month and $50.80 for 1680 kwh the next month how much should they expect to pay for 1840 kwh?
Found 2 solutions by Cromlix, tommyt3rd:
Answer by Cromlix(4381) About Me  (Show Source):
You can put this solution on YOUR website!
$50.40 for 1500kw
$50.40/1500 for 1 kw
$3.36 for 1kw
$50.80 for 1680kw
$5080/1680 for 1kw
$3.02 for 1 kw
Therefore 1840kw
should cost the Morgans
(3.36 + 3.02)/2 (Average)
£3.19 * 1840
$58.70.
Hope this helps.
:-)

Answer by tommyt3rd(5050) About Me  (Show Source):
You can put this solution on YOUR website!
We use the data to determine a line:


and using the first pair of data we can write:

%0D%0Ay-1500+=+325%28x-50.40%29%0D%0A

Now when y=1840 we get

%0D%0A1840-1500+=+450%28x-50.40%29%0D%0A


When we solve for x we get x=$51.16

:)