Savings In 25 Years?

Question

Monique makes annual contributions of $15,000 to her Roth 401(k) and in 30 years; she plans on retiring. If she averages a rate of return of 15%, how much will have in 25 years? please show mathematical steps in solving this question. thanks

Answer 1

15Kx15%+15K=M
(M+15k)*15%+=N

M=total return year 1
N=total return year 2

Then do that 23 more times.