SOLUTION: A car wash charges a flat rate for the first 8 minutes of washing time and also charges a certain amount for each additional minute of washing time. Gina took 12 minutes to wash h
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Question 174462This question is from textbook Algebra 2, Texas Edition
: A car wash charges a flat rate for the first 8 minutes of washing time and also charges a certain amount for each additional minute of washing time. Gina took 12 minutes to wash her car and it cost her a total of $5.00. Kris took 17 minutes to was his truck at a total cost of $6.25. Write an equation that models the total cost of a car wash as a function of the number of minutes spent washing a vehicle to find the slope of a line parallel to the line. This question is from textbook Algebra 2, Texas Edition
You can put this solution on YOUR website! A car wash charges a flat rate for the first 8 minutes of washing time and also charges a certain amount for each additional minute of washing time. Gina took 12 minutes to wash her car and it cost her a total of $5.00. Kris took 17 minutes to was his truck at a total cost of $6.25. Write an equation that models the total cost of a car wash as a function of the number of minutes spent washing a vehicle to find the slope of a line parallel to the line.
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This problem came up recently, except the phrase,"slope of a line parallel to the line" which I am not sure how this applies to this problem.
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Let a = cost per minute
Let b = flat rate for the 1st 8 minutes
;
Find a & b using the two equations
G's cost
a(12-8) + b = 5
4a + b = 5
:
K's cost
a(17-8) + b = 6.25
9a + b = 6.25
;
Use elimination, subtract G's equation from K's equation:
9a + b = 6.25
4a + b = 5.00
-----------------subtraction eliminates b, find a
5a = 1.25
a =
a = .25 per minute
:
Find b:
4(.25) + b = 5
b = 5 - 1
b = $4, cost for 1st 8 minutes
;
Check solutions in the K's equation:
9(.25) + 4 = 6.25
2.25 + 4 = 6.25
:
"Write an equation that models the total cost of a car wash as a function as the number of minutes spent washing a vehicle and find the flat rate for the first 8 minutes."
:
let m = no. of minutes to wash the vehicle
;
C(m) = .25(m-8) + 4
