We can simplify the expression as follows:

(5^(n+1) * 3^(n-1)) / 15^n

= (5^n 5 3^(n-1)) / (3^n * 5^n)

= (5 * 3^(n-1)) / 3^n

= 5 * (3^(n-1)) / 3^n

= 5 * (3^(n-1) / 3^n)

= 5 * 3^(-1)

= 5/3

Therefore, the simplified expression is 5/3.