Hi I have been working in this for 2 weeks now and I just can''t seem to figure it out. ok lets say Bill is 40 yrs old. His made 72,000 last year had 60,000. in annual expenses, has 12000 annually to invest. with an 8% apy. reducing the rate of return directly by the rate of inflation. What is the annual contribution to investments required to fully fund retirement @ age 65 if the last dollar spent is @ age 100.