A borrower bought a house for $200,000; he can obtain an 80% loan with a 30-year fully amortizing, 7% interest rate and monthly payment. Assuming that the marginal tax rate for the borrower is 28%. 1.What is the first month mortgage interest payment? 933.33 2.What is the first month mortgage interest deduction? 261.3 3. What is the first 5 months total taxable interest deduction: 1304.51

4. What is the effective first 5 months mortgage payment (after tax benefit): 4017.9

I have the answers listed but I need it worked out using only a financial calculator. Thank you so much!