Let's try something messier:
If we invest $400 a month at 8.4%, how much will we have in 40 years?
investment amount = $400
growth factor = $1.007
interest per period = .007
number of periods = 480
Invest $250 a month at 9%. How much will you have in 20 years?
One more... and this one we'll do yearly instead of monthly. (So, we'll have to assume it's compounded yearly.)
If we invest $5000 a year at 10%, how much will we have in 25 years?
investment amount = $5000
growth factor = $1.10
interest per period = .10
number of periods = 25
Invest $10,000 a year at 15%. How much will you have in 35 years?