Joanna made $104.50 for working 11 hours this week. How much money will she make if she works 15 hours?

104.5/11=9.5

9.5x15=$142.50

To get the money Joanna makes per hour, divide her earnings of $104.50 by 11. You should get $9.50, the amount she makes an hour. Then, since we are looking for how much she makes in 15 hours, multiply 9.5 by 15, and the result should be that Joanna makes $142.50 in 15 hours.