Find the value of n for which f(n)=g(n). What does that value mean in this situation?

Question

Marco owed his father $150 and began paying him back $20 at the end of each week, beginning November 1. Joni owed her father $130 and began paying him back $15 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) = 150 – 20n. What Joni owed her father in dollars at the end of n weeks can be represented by g(n) = 130 – 15n.  After how many weeks, Jonie and Marco each owed their fathers the same amount.

Answer 1

They owe the same amount when is f(n) = g(n),

150 - 20n = 130 - 15n

 

Can you solve for n?