Question 1184247
she saves 200 at the end of every other month.
the interest rate is .250% compounded monthly.
growth factor = (1 + .250/1200)


i used excel to come up with the answer.
the answer is, as far as i can tell:
her money at the end of 5 years will be equal to $6036.40, rounded to the nearest penny.


the excel printout looks like this.


<img src = "http://theo.x10hosting.com/2021/090601.jpg" >


<img src = "http://theo.x10hosting.com/2021/090602.jpg" >


there are other ways to get the answer, but this was the most straight forward and easiest to understand.


5 years is equal to 60 months.
time period 0 is the current time period.
time period 1 is the end of month 1.
time period 2 is the end of momth 2.
etc.


the formula used is as follows:


balance at time period 0 is 0.


balance at time period 1 is equal to (1 + .25/1200) * balance at time period 0 plus payment at time period 1.


since there was 0 balance at time period 0 and 0 payment at time period 1, the balance at time period 1 is also 0.


balance at time period 2 is equal to (1 + .25/1200) * balance at time period 1 plus payment at time period 2.


balance at time period 2 is therefore equal to (1 + .25/1200) * 0 plus 200 = 200.


balance at time period 3 is equal to (1 + .25/1200) * balance at time period 2 plus payment at time period 3.


balance at time period 3 is therefore equal to (1 + .25/1200) * 200 + 0 = 200.0416667 which rounds to 200.04 as shown.


balance at time period 4 is equal to (1 + .25/1200) * balance at time period 3 plus payment at time period 4.


balance at time period 4 is therefore equal to (1 + .25/1200) * 200.0416667 plus 200 = 400.083342 which rounds to 400.08 as shown.


this continues time period by time period to the end.