Question

You have 3 coins. One of them may be a fake that is either heavier or lighter than the real coins. Using a balance scale what is the best possible number of weighings that you need to always find the possible fake

Answer 1

Two weighing

Explanation:

In the context, it is given that one of the three coins is fake and the other two are real. It is also mentioned that the fake coin is either heavier or lighter than the other two real coins.

Now to find the fake coin, we take a balance scale and lace one coin on one pan of the balance and place the second coin on the other pan of the same balance. We keep the third coin aside.

Now we check the balance scale. If the scale is balance, then we can conclude that the coin that we kept aside is the fake coin as both the real coins have same weight.

Now we replace the one of the coin on the pan with the coin that is kept aside and check the balance. Remember now on the pan, there is one real coin and one fake coin. The balance scale will be dis-balance as the fake coin is either heavy or light than the real coin. Thus we can identify the fake coin.