Answer:
21 more hours
Step-by-step explanation:
Divide $75 by $5 to know how many hours he worked for. 75/5 is 15. So he worked for 15 hours so far.
Then find out how many hours will make $180. 180/5 = 36 hours. He needs to work 36 hours to earn $180 but he already worked 15. So, find the amount left. 36 - 15 is 21 hours.
