You have 10 identical cartons each holding 10 water bottles. All bottles weigh 10 oz. each, except for one defective carton in which each of the 10 bottles weighs 9 oz. only. A scale is available for weighing. Of course, weighing the cartons randomly one at a time will eventually locate the defective carton. The challenge is to develop a mathematical model that will determine the defective carton by using the scale exactly once.