3 hours of babysitting will earn them the same amount of money.
Josh = 8h + 9
Scott = 6h + 15
Number of hours of babysitting at which Scott and Josh will earn the same amount of money.
8h + 9 = 6h + 15
8h - 6h = 15 - 9
2h = 6
2h/2 = 6/2
h = 3
To check:
Josh = 8h + 9 = 8(3) + 9 = 24 + 9 = 33
Scott= 6h + 15 = 6(3) + 15 = 18 + 15 = 33