One of your professors has made you an offer you can't refuse. You are getting a four year research assistantship to earn your PhD after you receive your BS degree. The assistantship will pay you $2,600 per month starting in June, immediately after your graduation. Any courses you take will be free, so you will not have to pay any tuition during the four years. If you enter industry right now, you can expect to start at an annual salary of $61,500 with annual raises of 3.8%. If you consider the four years spent getting the PhD an investment, how much more should you receive in annual salary than the BS engineer after graduation if you want to recover your investment in the 10 years following your PhD degree? Use 7.5% compounded monthly for all your calculations.