A 15-year 8% bond with face amount 100 is callable (at the option of the issuer) on any coupon date in the 10th to 15th years. In the 10th year, the bond is called at par. In the 11th and 12th years the redemption amount is 115. In the 13th , 14th , and 15th years the redemption amount is 135. a) What price should a purchaser pay in order to ensure a minimum nominal annual yield to maturity of 6%? b) Find the purchasers minimum yield if the purchase price is 120.