if 15,000 is invested in an account that earns 1.2% simple interest, how much money is in the account after 5 years? How much money would be in the account if the interest rate was 0.1% instead?
If the interest is WITHDRAWN from the account at the end of each interest period, then it's $15,900.
If it's not, then interest will be compounded and the balance will be more than $15,900.