Eileen (from question7) wants a car that costs $ 12,000. How long would it have taken Eileen

Question:

Eileen (from question7) wants a car that costs $ 12,000. How long would it have taken Eileen to save for the outright purchase of the car if she did not have any credit card debt and used the interest payments to save for the purchase of the car? Eileen can invest funds in an account paying 8% interest.