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Cheryl’s birthday – solution
(Read the problem here) To get conclusion of the problem, we have three important information from Albert and Bernard’s conversation: Albert knows that Bernard does not know Bernard knows the answer after point 1 is known Albert knows the answer after point 2 is known So here we have initial options: May 15 …
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Blue or red? – solution
(Read the problem here) There are 13 blue balls. If we take only one blue ball, the ball will be back to the box. If we take two blu balls, both will be out from the box. It means blue balls can not get out alone. Means there always at least one blue ball in…
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Heaven or hell – solution
(Read the problem here) The woman should ask to anyone of them “Am I a woman?” If the guard say “Yes”, then she just go to the door, but if the guard say “No”, then she choose the other door. (…just for fun :))
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Four captives – solution
(Read the problem here) D and C can not see anyone, so it’s impossible for them to have any clue. A can see B and C. Seeing B and C’s hat, A still not getting the answer, so A can not say anything. B only can see C. But if B has the…
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25 and 28 years old – solution
(Problem can be read here.) Two days ago Andy still 25 but next year he will be 28. With that much gap, his birthday must be near new year, and the only possible solution is: Andy’s birthday is December 31, and ‘two days ago’ was December 30. So we have conversation on January 1. Two…