To calculate Joe's new hourly wage after the raise, we can use the following formula:
New hourly wage = Current hourly wage + (Current hourly wage * raise percentage)
New hourly wage = $8.15 + ($8.15 * 0.07)
New hourly wage = $8.15 + $0.57
New hourly wage = $8.72
So, after the 7% raise, Joe now makes $8.72 per hour.