24 February 2020

Followup puzzle

This is a followup puzzle to the previous one to understand why the one-black-dot case is not possible. Some find the answer to be controversial. To me the logic is bulletproof though.

So, it is the same problem as before except that the lady skips the portion where she asks the three men to raise their hands if they see at least one white dot. Instead, after removing the blindfolds, she straightaway asks “What color dot do you have on your forehead”.

After quite some thinking, the smartest person came up with the correct answer.

What was the answer and how did he figure it out?

For completeness sake, I am restating the whole problem here…

Three smart men were trying to find out who is the smartest of them all. Or was at least most logical and quickest thinker. To resolve that, they went to a woman who had the reputation of being the smartest of them all. She devised a quick problem for them. She blindfolded them and painted a dot on each of their foreheads.
She then told them “I have painted a dot on each of your foreheads. The dots are either white or black in color. I am going to soon open your blindfolds. You will be able to see other’s dots but not your own. Then I am going to ask you to guess the color of your own dot”.
Saying so, she opened their blindfolds.
“Okay, now guess what color is on your forehead”.
The three men started pondering and soon one of them – who was indeed a little smarter than the others – spoke up.
“Correct”, said the lady.
Question: What was the answer and how did he figure it out?

Posted February 24, 2020 by Rajib Roy in category "Puzzles


  1. By rajibroy (Post author) on

    The answer:
    In this case where there is no info given, each will look into the other people, see the same color dot on both and call out the same name. The reason for this is a little complicated.

    You have to think from the lady’s point of view. She has absolutely no idea who is the smartest. So, she has to create as unbiased a situation as she can to create a level playing field. If she puts on different dots, then she creates a different situation for each man. With no other info given, it is then reduced to a guessing game.

    Her only way to set it up would be to put the same color and see if the smartest of them all can realize what situation she is in.


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