Answer: you will have $305,596.89 after 45 years

Working notes for the above answer is as under

In this sum we have

, d = $125 (the monthly deposit

) r = 0.047 (5.6%)

k = 12 (since we’re doing monthly deposits, we’ll compound monthly)

N = 45,

since we’re looking for P45

Putting this into the equation:

Annuity Formula

P20 = 125 ( (1+  0.047/12 )45*12 -1)  /  (0.047/12)

In this formula:

PN is the balance in the account after N years. d is the regular deposit (the amount you deposit each year, each month, etc.) r is the annual interest rate

(in decimal form. Example: 5% = 0.05)

k is the number of compounding periods in one year.

Now we are solving the equation

P20 = 125 ( (1+0.047/12 )45*12 -1)  /  (0.047/12)

=$ 305,596.89

= So you will have $305,596.89 after 45 years.