Your are 17 years old (T=0) and want to retire at the age of 50 (T=33). If you want to retire with $1,000,000 and the interest rate is 10%, how much do you you have to set aside every year starting at the age of 18 (T=1). You will set the money every month for the next 33 years and you want to have $1,000,000 at T=33, 50 years old. Be careful with monthly. n = 33*12 and i=10%/12, just in case... It does not take much to become a millionare...