A water salesman collects water from a glacier and transports it in either small or large kegs. A small keg can hold 40 liters of water while a large keg can hold 100 liters of water. The salesman has available at most 30 small kegs and 10 large kegs. Since small kegs are easier to carry, at least twice as may small kegs must be used than large kegs. If he can transport at most 25 kegs total and at least 5 kegs must be large, how many of each should he use to maximize the total amount of glacial water he can transport?