A 20-year callable bond has a maturity value equal to its par value of 1,000 and semiannual coupons paid at a coupon rate of 8% convertible semiannually. The bond may be called at the end of 12 years for a call price of 1,300. The bond may be called at the end of 15 years for a call price of 1,200. Finally, the bond may be called at the end of 18 years for a call price of 1,100. If