Your cousin Marcus has asked your for some advice. He turned 25 today and just got out of the Army and started a really good job at GE. He is determined to retire at age 50 and given his family history and lifestyle, he will probably live to be 85. Marcus wants to know how much he needs to invest in his retirement account each month in order to be able to retire with $12,000 per month (end of each month) when he retires. You estimate that he can earn 12% up until age 50 and then should invest more conservatively at 5% during retirement. Marcus already has $5,000 saved up and invested for retirement in an IRA earning 8%. Notice that it is not accumulating at the same rate as his other investments. Take this into account when computing your answer. How much should he invest each month? Enter your answer as a positive number.

Please explain using Excel terminology.