public class MetricConversions {
   /**
	 * number of liters per inch
	 */
	public static final double LITERS_PER_GALLON = 3.785;
   /**
	 * convert gallons to liters
	 * @param gallons number of gallons
	 * @return number of liters
	 */
	public static double gallonsToLiters(double gallons) {
	   return LITERS_PER_GALLON*gallons;
	}
   /**
	 * convert gallons to liters
	 * @param liters number of liters
	 * @return number of gallons
	 */
	public static double litersToGallons(double liters) {
	   return liters/LITERS_PER_GALLON;
	}
}