Christina has just borrowed $12,000 at 9% compounded semiannually. Since she expects to receive a $10,000 inheritance

Question:

Christina has just borrowed $12,000 at 9% compounded semiannually. Since she expects to receive a $10,000 inheritance in two years when she turns 25, she has arranged with her credit union to make monthly payments that will reduce the principal balance to exactly $10,000 in two years.
a. What monthly payments will she make?
b. What will be the interest portion of the ninth payment?
c. Determine the principal portion of the sixteenth payment.