If a woman's last monthly payment interest was $647.91 and she paid an interest rate of 9%, what was her outstanding loan balance?

To determine the outstanding loan balance based on the last monthly payment interest and the interest rate, you can use the formula for calculating interest. The interest for the month can be calculated using the formula:

Interest = Principal × (Interest Rate / 12)

In this case, the monthly interest payment was $647.91 at an annual interest rate of 9%. First, convert the annual interest rate into a monthly rate by dividing by 12:

9% per year = 0.09 annual rate ÷ 12 months = 0.0075 monthly rate.

Now, you can rearrange the formula to find the principal (outstanding loan balance):

Principal = Interest / (Monthly Interest Rate)

Substituting in the values:

Principal = $647.91 / 0.0075

This calculation gives you an outstanding loan balance of approximately $86,388. Therefore, option C is correct because it accurately reflects the outstanding balance when you apply the interest payment of $647.91 at the monthly interest rate of 0.0075.