David abbot is buying a new house, and he is taking out a 3030-year mortgage. david will borrow $200 comma 000200,000 from a bank, and to repay the loan he will make 360360 monthly payments (principal and interest) of $1 comma 199.101,199.10 per month over the next 3030 years. david can deduct interest payments on his mortgage from his taxable income, and based on his income, david is in the 3030% tax bracket. a. what is the before-tax interest rate (per year) on david's loan? b. what is the after-tax interest rate that david is paying?