Higher education. The table lists thje average costs of attending a four year college in the U.S. during the 2005-2006 school year

College Sector            Tuition and fees      room and board

4-year public               $5941                       $6636

4-year private             $21,235                    $7,791

Russ’s parents invested money to a savings account earning an average of 4.5 percent interest, compounded monthly.

After 15 years they have exactly the right amount to cover the tuition, fees, room and board for Russ’s first year at a public college. What was their initial invetment. Round your answer to the nearest dollar.