Your aunt bought a new car. after three months of car payments she owed a total of $22,275 to the bank for the car loan. after 12 months, she owed $18,900 to the bank for the car loan. what was her average payment rate on the principal of the car loan during this time?

                                               I=p*r*t
This is the equation for how to solve the problem. For the equation, I put I=18,900 p=22,275 t=12. You are trying to get 18,900 because you are trying to get how much you have to pay them as the rate for the loan.
18,900=22,275*r*12 You do 22,275*12=267,300 since you can't multiply the rate yet. Then you do 267,300 divided by 18,900 and get 14% which is your answer.