Help me solve this Math word problem
Gloriaâ€™s washing machine is broken. Since her machine is pretty old, she doesnâ€™t want to spend more than $100 for repairs. A service call will cost $35 and the labor will be an additional $20 per hour. There are no other charges. What is the maximum number of hours that the repair person can work without the total cost exceeding $100? Please explain how you arrived at your answer. Thanks!