1 ,Polycorp has a debt equity ratio of 0.61.What is the correct debt ratio D/V that should be used in the WACC formula?

WACC = ke x E/V + kd x (1-t) x D/V

2, If a company with a rating of BBB has on issue debentures paying a coupon rate of 6% pa and the market yield on similar BBB securities is 7% pa, what is the correct cost of debenture capital (k_db), before tax,that the company should use when estimating the WACC using the textbook WACC formula? The riskfree rate is 5% pa.and the Rm is 13% pa