The annual college cost is expected to be $25,000 per year. A local firm sponsors a student loan program for the children of employees. No interest is charged until graduation, andthen the interest rate is 5% after graduation. Mary borrows $25,000 per year, and she graduates after 3 years. Since tuition must be paid ahead of time, we assume that she borrows the money at the start of each year. Starting from year 4, Mary plans to pay off the loan in 6 years by making equal payment at the end of each year.

How much is the yearly payment? (please provide workings)