Final answer:
If you invest $1,000 in an account with a 20% interest rate compounded annually, you will have $1,200 at the end of one year.
Step-by-step explanation:
If you put $1,000 into an account with a 20% interest rate, compounded once per year, you can calculate the amount of money you'll have at the end of the year with the compound interest formula:

In this case, P = $1,000 (the principal amount), r = 0.20 (the annual interest rate), n = 1 (since interest is compounded once per year), and t = 1 year. Plug these values into the formula to get:
A = $1,000(1 + 0.20/1)1∗1 = $1,000(1 + 0.20) = $1,000 ∗ 1.20 = $1,200.
By the end of one year, you will have $1,200 in your account.