An equation like [tex]8x+15=The Final Price[/tex] would work cause it's 15 plus 8 times the hours used.
If you paid 63 then you would have [tex]8x+15=63[/tex]
Solve it by first subtracting 15 over and having
[tex]8x=48[/tex]
Divide both sides by 8 and finally get
[tex]x=6[/tex]
