can you answer this in excel:

You just celebrated your 21st birthday and you decide it is a good time to start investing for your retirement at age 65. You have decided to start by determining how much you will need. You figure you will need approximately $5,000 per month during retirement until you turn 80, and then you expect to need $8,000 per month (to cover additional medical and support needs) until the end of your life. Given your family history, you expect to live until 90. You want to make your first withdrawal on the first day of your retirement and continue to withdraw your funds at the beginning of each month thereafter. During retirement, you estimate that your funds will continue to earn 0.25% per month. based on monthly compounding.

a. How much will you need to have saved up by the time you retire? (5 marks)

b. How much will you need to contribute, starting next month, if you want to achieve your retirement goals? (3 marks)