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Suppose if there are 8 bags of wheat, 7 of which weigh the same amount. However, there is one that weighs less than the others. You are given a balance scale used for weighing. In less than three steps, figure out which bag weighs less than the rest?
Answer:
Immediately, take any 2 of the bags and place them to the side. Weigh 3 of the remaining six bags against the other 3 bags. If these bags weigh the same, that means the bag that weighs less must be one of the two that you immediately placed to one side. If this is the case, weigh the 2 bags you placed to one side against each other to find out which one weighs less. You've now found in your bag.
However, upon weighing the sets of 3 bags against one another you find that one set weighs more than the other set, place one of the bags from the set of heavier bags aside and weigh the remaining two bags to find out which one is heavier. If they are of equal weight, the you know that the bag you place to one side is the bag you're looking for.
However, upon weighing the sets of 3 bags against one another you find that one set weighs more than the other set, place one of the bags from the set of heavier bags aside and weigh the remaining two bags to find out which one is heavier. If they are of equal weight, the you know that the bag you place to one side is the bag you're looking for.