Problem
Sarah would like to support the university education of her grandson, Stephen, who will start his university exactly three years from today. Stephen will be at the university for four years, and he has to pay his tuition at the beginning of each year. The tuition each year will be $4,000. How much Grace needs to invest today to ensure that she can make the four payments for her grandson? Assume that Sarah can earn a 7% return per year on her investments (compounded annually).