A CMO is being issued with 3 tranches. The A tranche will consist of $100MM of principal and have a coupon of 7%. The B tranche will consist of $50MM of principal and have a coupon of 7%. The Z tranche (accrual tranche) will consist of $25MM of principal and have a coupon of 7%. The mortgages backing the security issued are FRM at 7.0% with 30 year (360 month) maturities and monthly payments. Priority payments will be made to the A tranche and will include the promised coupon. Interest will be accrued to the Z tranche until A is completely repaid. The B class will receive interest payments only until the A class is repaid. The A class will then receive all remaining CFs from the pool that year. After A is repaid, B will receive priority principal payments. The Z class will accrue interest at 7% until both A and B are repaid. It will receive current interest and principal payments at that time. Assume there is no prepayment or servicing fees.

5) What is the balance of the Class B tranche at the end of year 9?

6) What is the balance of the Class Z tranche at the end of year 12?