A baseball player hits the ball and then runs down the first base line at 17 ft/s. The first baseman fields the ball and then runs toward first base along the second base line at 20 ft/s. Determine how fast the distance between the two players is decreasing at a moment when the hitter is 4 ft from first base and the first baseman is 3 ft from first base. (Use decimal notation. Give your answer to one decimal place.) distance change: ft/sec