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
