Answer:
n = 22
Step-by-step explanation:
We will use the formula for the present value of an ordinary annuity :

where P = periodic payment
r = rate per period
n = number of periods
Given P = PMT = $400, P.V. = $8,000, i = 0.01, and we have to find n.
Now we put the values in the formula

After rearranging we have


= 1 - 0.2
= 0.8
Taking log on both sides
-n log 1.01 = log 0.8
= 22.4257
Therefore, n = 22
So there are total 22 payments