Marco owed his father $210 and began paying him back $20 at the end of each week, beginning November 1. Joni owed her father $180 and began paying back $10 at the end of each week, beginning on the same day. What Marco owed his father in dollars at the end of n weeks can be represented by f(n) = 210 − 20n. What Joni owed her father in dollars at the end of n weeks can be represented by g(n) = 180 − 10n.
Find the value of n for which f(n) = g(n). What does that value mean in this situation?

After _____ weeks, Jonie and Marco each owed their fathers the same amount