9. Zitrone Motors has 36 million shares outstanding with a share price of $43 per share. In addition, Zitrone has issued bonds with a total current market value of $1720 million. Suppose Rumolt's equity cost of capital is 10%, and its debt cost of capital is 6%.

a. What is Zitrone's pre-tax WACC?

b. If Zitrone's corporate tax rate is 30%, what is its after-tax WACC?

10. Summit Builders has a market debt-equity ratio of 0.60 and a corporate tax rate of 40%, and it pays 8% interest on its debt. By what amount does the interest tax shield from its debt lower Summit's WACC?

WACC is lowered by ____%. (Round to two decimal places.)