14 Σ [(1.3^n) * (150)]n = 0
Using the sigma notation to find the sum of his first 15 payments, each of the possible values of n (from 0 to 14) are substituted into the equation. After which, each of the results are then added to each other. Also, the problem states that only the first 15 payments are to be included in the notation. This shows that the series is limited and is finite. Therefore, it is a convergent series.