New Jet Airlines plans to issue $14-$year bonds with a par value of $$1,000$ that will pay $$60$ every six months. The bonds have a market price of $$1,220.$ Flotation costs on new debt will be $4\%$ of the selling price. If the firm has a $35\%$ marginal tax bracket, compute the following:

a$.$ Yield to maturity of debt

b$.$ After$-$tax cost of existing debt

c$.$ After$-$tax cost of new debt