Q3. You are going to contribute some money to your retirement fund at the beginning of this year and each of the next 39 years. You have the following assumptions: I. Initial balance for year 1 is assumed to be 0 . II. Suppose during Year 1 ,your salary is $40,000 and your salary increases by 5 percent each year until your retirement. III. You want to contribute the same percentage of your salary each year while you are working for your retirement. IV. When you retire in 40 years, you plan to withdraw $100,000 per year for 20 years (starting year 41 ) and will not make any contribution to your retirement during the 20 years. You also Assume the following retirement investment portfolio: 1. First 20 years of your investing, the investments will earn 10 percent per year V. During all other years, your investments will earn 5 percent per year Part l: Assume all contributions and withdrawals occur at the beginning of the year before investment returns are received, please set up the retirement problem to find out the minimum percentage of your salary you should save for your retirement in order for you to make the withdrawals. Part II: Assume that withdrawals occur at the end of each year after the investment returns are received and contributions occur at the beginning of each year before the investment returns are received, please set up the retirement problem to find out the minimum percentage of your salary you should save for your retirement in order for you to make the withdrawals