Suppose you have 4 cards - each will have one side with an alphabet and another with a number.
The side of the 4 cards shown to you are:
A; C; 3; and 6
There is a rule. If a card has a vowel on one end, then it has an even number on the other side.
Question : Which card(s) must you open to prove the above rule is true? I need to limit it to the minimum number of cards to open.
The same question can be re-framed as follows:
Suppose there are 4 persons sitting in a bar.
One is drinking beer; Another Pepsi; the 3rd fella is aged 16; and the 4th is aged 25
There is a rule. Only those aged 25 and above can drink beer.
Question: Who should you check to prove the above rule is true? Similarly, to limit to the minimum number of persons.
Answer: This should be easy - The one drinking beer (A) and the 3rd fella who is aged 16 (3).
What is the morale of the story? This game is designed to prove that our human brain is more sophisticated when it comes to people and less so with abstract concepts such as numbers and letters.
So next time when you are stuck. You just need to re-frame the question. Using analogy and story will help.