MATH QUESTION kinda stuck on it

Question

You want to purchase a new car in 3 years and expect the car to cost $25,000. Your bank offers a plan with a guaranteed interest rate of APR = 5.5% if you make regular monthly deposits. How much should you deposit each month to end up with $25,000 in 3 years? How much the final value comes from actual deposits and how much from interest? 

Answer 1

Here's a formula for the monthly payment required (there are others as well)

PMT = (A * APR/n)/[(1 + APR/n)^ny) - 1]

In this case A = 25000, APR = 0.055, n = 12, y = 3

Plug them in and calculate in the correct order to get PMT = $640.31/mo. (may differ by a little bit based on how many decimal places you use and rounding).

Total paid is $640.31 x 36 = $23,051.36. The balance of the $25,000 comes from the interest earned.