How much would I pay overall on $11,000 if payments are over 3 years compounded annually at 11%. I originally came up with $12,964.53 divided by the thirty-six months, this comes out to $360.13 per month. The total interest on this would equal $1,964.53   My instructor said I came out with the wrong answer. I don’t know what I’m doing wrong. I would really like to see the formula as well Also, here is the original question   For buying the dishmachine through the vendor’s credit payment plan, you would be charged 11 percent interest over three years on the $11,000 cost of the dishmachine while making monthly installment payments. For this option you will need to calculate the total future amount that will be paid based on an initial amount of $11,000 for the dishmachine and 11% interest for the duration of the loan which is three years.