Before tax cost of debt and after tax cost of debt: David Abbot is buying a new house, and he is taking out a 30 year mortgage. David will borrow $193,000 from a bank, and to repay the loan he will make 360 monthly payments of $1220.40 per month over the next 30 years. David can deduct interest payments on his mortgage from his taxable income, and based on his income, Davis is in the 30% tax bracket.

a. what is the before tax interest rate (per year) on David's loan?

b. what is the after tax interest rate David is paying?