please show calculations.

11) You are planning for your retirement. You need to calculate how much you will need to have at the beginning of your retirement life in order to withdraw $4,000.00 monthly during 30 years. You are confident that you can find an investment vehicle offering 5% annual returns (compound monthly) when you start you retirement life. Show your work. 12) The current monthly mortgage payment is $2,300. If you were to refinance the mortgage, how long it would take in terms of months) to break-even assuming the following: current mortgage balance is $175,000 new mortgage rate is 3.5% 30 years to mature Pre-payment penalty is $0.00 Closing costs are $6,500