4. What is the net present value of the following stream of cash flows assuming the opportunity cost rate is 15%? Solve NPV using each cash flow and the NPV function in Excel (use Excel formulas and basic PV/FV techniques). Year 0: -$10,000 Year 1: $4,000 Year 2: -$2,000 Year 3: $5,000 Year 4: $3,000 Year 5: $6,000 5. You are planning for retirement. Use the following information to yanswer the question. a. The expected inflation rate from now until retirement is expected to be 2.5%. b. Your current income/expenses are $100,000 and that is the same standard of living you will have in retirement. To estimate expenses, you can take the average of the first year in retirement and last year in retirement and assume that is the value for each year in retirement. c. You can expect to earn 5% on your money in retirement. d. You are 35 when you graduate and expect to work until you are 65. e. Your life expectancy is 87. f. You will leave your heirs $1,000,000 upon your death