A car wash charges a flat rate for the first 8 minutes of washing time and a certain amount for each additional minute. Gina took 12 minutes to wash her car and it cost her a total of $5.00. Kris took 17 minutes to wash his truck at a total cost of $6.25.
How much is the flat rate for the first 8 minutes? Show the equation used to find the answer.
Answer (2)
flat rate = x
so for the first eight minutes they both have the same rate so this is also true Gina took 4 minutes to wash her car and it cost her a total of $5-x Kris took 9 minutes to wash his truck and it cost him a total of $6.25-x so for overtime 4mins=5-x, 9mins=6.25-x 4 times 9 = 36 so 36 mins = (45-9x)=(25-4x) so 45-9x=25-4x subtract 25 from both sides and get 20-9x= -4x subtract add 4x to both sides 20-5x=0 factor out the five 5(4-x)=0 (4-x) must =0 4-x=0 add x to both sides 4=x it cost $4 for flat rate
The flat rate for the first 8 minutes of washing at the car wash is $4.00. This was determined by setting up equations for two customers based on their washing times and total costs. By solving the equations, we find that the flat rate is $4.00.
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