SOLUTION: 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 fla

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Question 180499: 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)
Please explain steps
Found 2 solutions by stanbon, Mathtut:
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
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.

Answer by Mathtut(3670) (Show Source):
You can put this solution on YOUR website!
let x be the flat fee and y be the additional fee
:
x+4y=63.........eq 1
x+6y=87.........eq 2
:
subtract all terms from eq 2 from eq 1
:
x terms will be eliminated because x-x=0. We are left with 4y-6y=63-87
:
-2y=-24
:
additional fee
:
take y's found value and plug it into either eq 1 or 2
:
I am using eq 1
:
x+4(12)=63
:
flat fee