Yes, No, I Don’t Know

Your friend is thinking of a number among 1, 2, and 3. You can ask him just one question, to which he is allowed to answer only with “yes”, “no”, or “I don’t know”. What would you ask him in order to find his number?

You can ask him the following:

“If I am thinking of a number among 1 and 2, is your number going to be bigger than mine?”

If your friend’s number is 1, he will say “no”. If his number is 2, he will say “I don’t know”. If his number is 3, he will say “yes”.

+ posts

We do not know where this puzzle originated from. If you have any information, please let us know via email.

Notify of
Inline Feedbacks
View All Comments