A karate studio charges $35 for the first course and $22.50 for each course after that- even if the student leaves the course early. Cena paid $170 for her son to take courses. How many courses did he 2

A karate studio charges $35 for the first course and $22.50 for each course after that, even if the student leaves the course early. Cena paid $170 for her son to take courses. How many courses did he take?6 courses7 courses8 courses10 courses