Martin Inc.s bonds will mature in 10 years. The coupon interest rate on the bonds is 6.75 percent, paid at the end of each year. The bonds have maturity values of $1,000 each and are currently selling at a market price of $1,144. What is the yield to maturity?

For the problem above, if the companys marginal tax rate is 25 percent, what is the after-tax cost of existing debt?