23. (Financial planning) Mary has just completed her undergraduate degree from Northwestern University and is already planning to enter an MBA program 4 years from today. The MBA tuition will be $50,000 per year for 2 years, paid at the beginning of each year. In addition, Mary would like to retire 15 years from today and receive a pension of $60,000 every year for 20 years, with the first pension payment paid out 15 years from today. Mary can borrow and lend as much as she likes at a rate of 7%, compounded annually. In order to fund her expenditures, Mary will save money at the end of years 0– 3 and at the end of years 6– 14.