The Most Intelligent Prince

Logic Level 2

A king wants his daughter to marry the smartest of 3 extremely intelligent young princes, and so the king's wise men devised an intelligence test.

The princes are gathered into a room and seated, facing one another, and are shown 2 black hats and 3 white hats. They are blindfolded, and 1 hat is placed on each of their heads, with the remaining hats hidden in a different room.

The king tells them that the first prince to deduce the color of his hat without removing it or looking at it will marry his daughter. A wrong guess will mean death. The blindfolds are then removed.

You are one of the princes. You see 2 white hats on the other prince's heads. After some time you realize that the other prince's are unable to deduce the color of their hat, or are unwilling to guess. What color is your hat?

Black White

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3 solutions

Hardik Siloiya
Feb 10, 2016

White.

The king would not select two white hats and one black hat. This would mean two princes would see one black hat and one white hat. You would be at a disadvantage if you were the only prince wearing a black hat.

If you were wearing the black hat, it would not take long for one of the other princes to deduce he was wearing a white hat.

If an intelligent prince saw a white hat and a black hat, he would eventually realize that the king would never select two black hats and one white hat. Any prince seeing two black hats would instantly know he was wearing a white hat. Therefore if a prince can see one black hat, he can work out he is wearing white.

Therefore the only fair test is for all three princes to be wearing white hats. After waiting some time just to be sure, you can safely assert you are wearing a white hat.

Will Hawkes
Feb 11, 2016

Scenario 1. If any prince can see 2 black hats, then they can immediately deduce that their hat is white and so they can claim the princess's hand.

Scenario 2. If any prince can see 1 black hat and 1 white hat, and no other prince has quickly come forward identifying their own hat as white (as established in Scenario 1), then they can deduce that their hat isn't black and has to be white, and so they can claim the princess's hand.

Scenario 3. If any prince can see 2 white hats, and neither Scenario 1 (someone can see 2 black hats) nor Scenario 2 (someone can see 1 black hat and 1 white hat) has happened, then that prince can consequently deduce that there are no black hats anywhere, so their hat isn't black and has to be white, so they can claim the princess's hand.

[round of applause and wedding bells]

So it's interesting that the winner is always wearing a white hat. Thus three white hats is the only fair competition.

Same method

Sharan Srinivasan - 5 years, 3 months ago
Xeeshan Alam
Jul 18, 2018

Easy😐😐 by Question ,"you see 2 white hats on the other prince's heads" Note... you can be any Prince. First Second or third prince U see 2 white hat😋😋 Simply white Hat

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