Question 1123828
cigarettes cost 7 collars a pack.
smoker smokes 15 packs a month.
15 * 7 = 105 dollars per month spent on cigarettes.


invest that 105 dollars at the end of each month for 65 - 21 = 44 years at 4% annual return will yield a future value as shown below.


use the online calculator at <a href = "https://arachnoid.com/finance/" target = "_blank">https://arachnoid.com/finance/</a>


here's a display of the use of that calculator to solve this problem.


<img src = "http://theo.x10hosting.com/2018/092201.jpg" alt="$$$" >


your inputs to this calculator would be:


present value = 0
future value = 0
number of time periods = 44 years * 12 = 528 months.
payment per month = 15 * 7 = 105
interest rate per month = 4% per year / 12 = .333333.....%.
payment is made at the end of each month.


you would then click on FV and the calculator tells you that you would have 155,056.68 dollars when you're 65 years old.


528 * 105 = 55,440 of that would be money you invested over the 44 year period.


the rest is interest earned from those payments.