4. Your father has decided to save $500 each month in a trust account to help fund his early retirement. Payments will be made at the beginning of each month for 20 years. Following that 20-year period, your father will withdraw 25 equal annual payments, with the first payment to be made at the end of year 21. The funds will be invested at a nominal (APR) rate of 4.5 percent, with monthly compounding, during both the accumulation and the distribution periods. a. How large will each of your father's 25 retirement period payments be? (6 points) b. If your father can also invest a lump sum today of $35,000 from money he just inherited to supplement his own payments (same investment fund in Part (a) above), how much will his total annual payment be during each of his retirement years? (3 pts) 5. You originally borrowed $300,000 from a bank with an APR of 10% for a 30-year fixed rate mortgage with monthly payments. Five years later interest rates have fallen to an APR of 8% and you are considering refinancing the loan with a new 15-year fixed rate mortgage with monthly payments. Should you refinance? Justify your answer by calculating all appropriate metrics. (6 pts)