Xi is planning for his son's college education to begin ten years from today. He estimates the yearly tuition, books, and living expenses to be $20,000 per year for a four-year degree (given his son is taking the fixed tuition plan). How much must Xi deposit today, at an interest rate of 7 percent, for his son to be able to withdraw $20,000 per year (at the beginning of the year) for four years of college? Hint: First payment on Year 10.