<PRE><B>Question 180499</B>
There is a flat fee x plus y dollers for every hour
A person used 4 hours and had a fee of 63
another person used it for 6 hours and had a fee of 87
What is the value of the flat fee (x) and additional fee (y) 
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Points:
(4,63) and (6,87)

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slope = (87-63)/(6-4) = 24/2 = 12
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intercept:
63 = 12*4 + b
b = 63-48
b = 15
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Equation:
y = 12x + 15
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Flat fee = $15
Additional fee = $12 per hour
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Cheers,
Stan H.</PRE>