Joe Sullivan invested 9000 dollars at the end of each year for 20 years.
THen the interest rate that he is receiving is 8% per year.
Let's solve for the total money he will receive for 20 years.
=> 9000 0.08 = 720
=> 9000 + 720 = 9720 dollars per year.
=> 9720 20 years = 194 400 dollars in 20 years