1. The problem statement, all variables and given/known data Question is attached. 2. Relevant equations sn = [a(1-r^n)]/(1-r) 3. The attempt at a solution I know the more compounding periods there are, the better. The part that I'm stuck on is what values to put for r and n, since the rate that he is making payments is different from the number of compounding periods. When I use this equation, (using 1 year of payments for example), I'm getting a confusing answer. I used 12 for n, since there are 12 payments being made in 1 year, but I think that's the problem? Since n is supposed to be the number of compounding periods. But then how do I show that there are 12 payments being made?