Puzzles/Decision puzzles/12 Coins
You are handed 12 metal coins which look alike. However, one of them is fake and weighs either more or less than each of the other 11 coins (which all have identical weight). To measure or compare weights you have only a pan balance that tips down to the side with the greater weight or stays in balance if both pans hold equal weights.
With how many weightings can you find the fake coin and also determine if its weight is more or less than the weight of the other coins? How do you do it?