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