Lisa the trainer has two solo workout plans that she offers her clients: Plan A and Plan B. Each client does either one or the other (not both). On Friday there were 12 clients who did Plan A and 2 who did Plan B. On Saturday there were 3 clients who did Plan A and 5 who did Plan B. Lisa trained her Friday clients for a total of 21 hours and her Saturday clients for a total of 12 hours. How long does each of the workout plans last?