4. Time Value of Money: (Use a financial calculator to help you) a. How many months does it take my investment to be doubled if interest rate is 4.5% compounded annually? Use both the official and the unofficial ways. b. A bank will pay you $200 at the end of each year for your lifetime if you deposit $6,000 in the bank today. If you plan to live forever, what interest rate is the bank paying? If inflation rate is expected to be 1.5% per year forever, determine the real interest rate the bank is paying using both the exact and the approximate method. c. You have reached age 60 with a modest fortune of $3 million and are considering carly retirement. How much can you spend at the end of each month for the next 20 years? Assume the nominal interest rate is stable at 7% compounded monthly. d. In order to reach the modest fortune of $3 million, you want to start saving right away. Suppose you want to contribute $1,000 at the start of every two weeks, when do you need to start contributing? Assume the nominal interest rate is stable at 7% compounded biweekly