Solution

The box which was placed on 6 th shelf contained 20 kg of Sugar. Using the above hints, we have: Box C was not the lightest and Box F, was the heaviest. There are three boxes between Box F and Box D and Box D was placed below the shelf on which Box F was placed. E was placed immediately above the box which was heaviest. Here, we have two possible scenarios in which we can use the above hints accordingly. Here, we will make a mental note of information that Box C was not the lightest. Box C was placed above the shelf on which Box F was placed but not on the even numbered shelf. Box A, contained 30 kg of Sugar, and was placed either at the top or bottom shelf. At this point we cannot use the above hints in case 12 so we can say that case 12 is an invalid case . Box B was placed immediately below the box which contained 18 kg of Sugar and immediately above the box which contained 12 kg of Sugar. Here, we have two possible scenarios in which we can use the above hints in case 11 accordingly. Box G was placed at one of the even numbered shelves and contained 27 kg of Sugar . At this point we cannot fix the position of box G according to the above hints in case 11-B so we can say that case 11-B is an invalid case .