A rental car company is running two specials. Customers can pay $20 to rent a compact car for the first day plus $10 for each additional day, or they can rent the same car for $40 the first day and $5 for every additional day beyond that. Clarence notices that, given the number of additional days he wants to rent the car for, the two specials are equivalent. How many additional days does Clarence want? Write a system of equations, graph them, and type the solution.