Red Mark

Written on 12:54 am by Vja Students

While a red mark was placed on the forehead of each of three blindfolded women seated facing each other in a circle, they were told that the mark might be either red or white. Upon removal of the blindfolds, each was to raise her hand if she saw at least one red mark, and then to take it down if she could logically deduce the color of her own mark. All three hands were quickly raised, but then one of them lowered her hand. How did she know?

Solution::

This is a variation of the above problem, but very hard for some people to solve. Everyone can see that each woman could be thinking that her own forehead might be red or white because the other two women could be raising their hands because of each other. Again, this is the point where most people stop, and indeed, where the women stopped while all three hands were up. The trick to solving this problem is to REALLY put yourself into the smart woman's shoes. If you REALLY were she, you'd say, either I have a white spot or a red. Suppose you had a white spot. Then the other two women would be looking at one white spot and one red. They would each quickly figure out that that only reason the others hand was up was because of their own red spot. The fact that neither of them figured it out was the tip off to the first that she must also have a red spot. Most people put themselves in the place of the first person, but to solve this one, you must then also put yourself in the place of a second woman.


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3 Comments

  1. Name does not matter to the Blog |

    The question is not clear. If all the three of them are facing each other. Then they can very well tell what is the colour on each of their head

     
  2. Anonymous |

    excellent..

     
  3. Anonymous |

    too good...

     

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