Question 1157349: The phone company A Fee and Fee has a monthly cellular plan where a customer pays a flat monthly fee and then a certain amount of money per minute used on the phone. If a customer uses 420 minutes, the monthly cost will be $64. If the customer uses 910 minutes, the monthly cost will be $113.
A) Find an equation in the form
y=mx+b
,
where x
is the number of monthly minutes used and y
is the total monthly of the A Fee and Fee plan.
B) Use your equation to find the total monthly cost if 863 minutes are used.
Found 2 solutions by josgarithmetic, mananth:
Answer by josgarithmetic(39617)   (Show Source):
You can put this solution on YOUR website! --------------------------
If a customer uses 420 minutes, the monthly cost will be $64. If the customer uses 910 minutes, the monthly cost will be $113.
-------------------------
x minutes
y monthly cost
points (x,y) are (420,64) and (910,113).
 --------------simplify and put into y=mx+b form.
Answer by mananth(16946)  (Show Source):
You can put this solution on YOUR website!
If a customer uses 420 minutes,
the monthly cost will be $64.
C =mx + y
C= total cost
m is cost per minute
y is the fixed amount per month
64 =420m +y
If the customer uses 910 minutes, the monthly cost will be $113.
113 =910m +y
420.00 m + 1.00 y = 64.00
910.00 m + 1.00 y = 113.00 .............2
Eliminate y
multiply (1)by -1.00
Multiply (2) by 1.00
-420.00 m -1.00 y = -64.00
910.00 m 1.00 y = 113.00
Add the two equations
490.00 m = 49.00
/ 490.00
m = 0.10
plug value of m in (1)
420.00 m + 1.00 y = 64.00
42.00 + 1.00 y = 64.00
1.00 y = 22. costy = 22.00
Ans m = 0.10
y = 22.00
cost per minute 10 cents
Fixed monthly charge $ 22
the total monthly cost if 863 minutes are used.
plug m,y,x to get monthly
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