My name is Kimberlee. I am in the 7th grade. My math question is David earns $6.00 per hour plus $9.00 for every extra hour he works over 40 hours per week. If David earned $285.00 last week, how many extra hours did he work?

Davis is paid $6 per hour for the first 40 hours he works in a week. Thus if he works 40 hours he makes 40 x $6 = $240. He was actually paid $285 so he worked more than 40 hours. In fact he worked long enough to make $285 - $240 = $45 extra. For the extra hours he was paid $9 per hour. How many extra hours would he have to work to make $45?