4. Upon starting your first job, you consider a plan to retire after 40 years. During your retirement, you estimate that you will need $100,000 per year for 30 years, after which you anticipate that you will pass away.

a) What constant amount must you save every year over the next 40 years if your investments earn a return of 5% every year? (While it may be an oversimplification, lets also assume that all savings and all withdrawals are made at the end of the year in which they are earned.) b) Same as above, except that you wait ten years before you start saving; and you save for thirty years instead of 40. c) Comment on the results in a) and b). -- It will be helpful to draw a cash flow diagram, or other relevant figure, to guide my thinking. For questions that ask for an answer involving words please respond in complete and concise sentences. Please state explicitly any assumptions that you think you need to solve a problem. Unless specified otherwise, all interest rates in this problem are compound interest rates.