A baseball player hits the ball and then runs down the first base line at 18 ft/s. The first baseman fields the ball and then runs toward first base along the second base line at 16 ft/s. Determine how fast the distance between the two players is decreasing at a moment when the hitter is 16 ft from first base and the first baseman is 12 ft from first base. (Use decimal notation. Give your answer to one decimal place.) distance change: ft/sec