Gronseth Drywall Systems, Inc., is in discussions with its investment bankers regarding the issuance of new bonds. The investment banker has informed the firm that different maturities will carry different coupon rates and sell at different prices. The firm must choose among several alternatives. In each case, the bonds will have a $1 000par value and flotation costs will be $40per bond. The company is taxed at 30%.Use the approximation formula to calculate the after-tax cost of financing with the following alternative.

coupon rate = 11%

time to maturity = 13 years

premium or discount 200$

The after-tax cost of financing using the approximation formula is ____%