Help me solve this Math word problem

Help me solve this Math word problem

Gloria’s washing machine is broken. Since her machine is pretty old, she doesn’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!