You want to retire in 30 years and be able to withdraw the equivalent of $90,000 per year (in today's dollars) from a retirement fund. Assume 3% inflation. You plan to be retired for 20 years. Assuming you can earn 12% on your investments BEFORE retirement and 7% on your investments DURING retirement, how much will you need to save per month in order to be able to fund this retirement?

and

You want to retire on the equivalent of $50,000 per year in todays money. Inflation is expected to be 3%. You will retire in 30 years. You will earn 10% annually on your investments from now until retirement and you will earn 8% DURING retirement (which is expected to last 20 years). How much do you need to save per MONTH in order to fund this retirement?

I am in the middle of a quiz and am completely drawing a blank. I use Excel spreadsheet with formulas to try and get the answers....can't figure any of it out for whatever reason. I don't expect you to do my work for me....but maybe you could make up a problem that is similar that I can emulate. I don't know how to use long form calcs....so FV function, rate, pmt, nper...etc will help.