compounded continuously interest question...?

Question

can someone do it, and see if i get the same answers...?


One person invests $1200 at the end of every year from 40 years. A
second person invests $100 at the end of every month for 40 years. Another person invests
$200 at the end of every month for 20 years. All three receive 6% interest compounded
continuously. Compare the individuals’ savings at the end of the time periods.

Answer 1

Presuming continuous compounding exp(.06*(T-t)) then the answers are $194509.80, $199,962.80 and $307352.70. The above answer was periodic compounding, they also forgot to stop the contributions at year 20. I checked it out on a spread sheet. It is easy. Prior period principal*exp(.06/12)+additions in period, in each cell for 480 cells.

Answer 2

assuming you mean that the interest rate is an annual one, then:

First person would have $185714 at the end of 40 yrs
Second person would have $199149 after 40 yrs
Third person would have $92408 after 20 yrs, if this person would have invested for 40 yrs the amount would be $398298