The graph shows the total cost, in dollars, to rent a bicycle for a certain number of hours. The total cost includes a flat fee plus an hourly rate. If a customer rents a bicycle for 3 hours, what is the total cost, in dollars?

[Graph Description: A line segment starts at (0, 10) and goes up to (5, 35). The x-axis is 'Hours Rented' from 0 to 5. The y-axis is 'Total Cost ($)' from 0 to 40. The line passes through (1, 15), (2, 20), (3, 25), (4, 30).]