Odd One Out
You have 19 eggs. 18 of them have the same weight and 1 of them is different, but you do not know if it is heavier or lighter than the others.
Using the best possible strategy, in the worst case scenario, how many weighings do we need to perform in order to correctly identify the different egg?
Edit: You do not necessarily need to find if the egg is heavier or lighter than the others.