Sony bonds were issued 8 years ago with a coupon rate of 9%. The bond has 2 years left to maturity and is currently selling for $880. The firm typically falls under a 40% tax rate. Based on this...

Sony bonds were issued 8 years ago with a coupon rate of 9%. The bond has 2 years left to maturity and is currently selling for $880. The firm typically falls under a 40% tax rate. Based on this informaiton, what is their after-tax cost of debt? Assume coupon payments are made semiannually.