help with 3 &4

Three years ago, the Morgan Co. issued 15 -year, 6.5 percent semiannual coupon bonds at par. Today, the bonds are quoted at 100.6. What is this firm's pretax cost of debt? 6.83%6.43%6.27%6.08% The Nickel and Copper Store has a cost of equity of 8.6%, a pretax cost of debt of 7.2%, and a tax rate of 32%. What is the firm's weighted average cost of capital if the debt-equity ratio is 0.62? Your