Friday, 18 March 2011

Card piles

Answer to yesterday's riddle: He is a priest, and he marries other couples.

I actually laughed at how many people thought he's dead! Anyway, this next one is a toughy, and isn't too intuitive. There's no trick involved (well, maybe a little) but rather a bit of thinking:

You are blindfolded and given a deck of 52 cards. You are told that exactly 13 random cards in this pack are facing up, while the other 39 are facing down. Without removing your blindfold, you must divide the deck into two piles such that both contain the same number of face-up cards. If you like, the piles need not be the same size.

26 comments:

  1. Quite interesting. When will you post the solution? Eagerly waiting for it.

    I can suggest you another site with brain storming brain teasers. I have tried it and believe me if you are a brain teasers lover who loves to solve brain teasers then try solving out these Brainteasers and find out how smart you are.

    Best of Luck!!!

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  2. Oh wow...Um? I don't even know. o_o

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  3. cut the cards in half(literally, like with scissors). The one half is on in the one pile and the other half in the other

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  4. Oh man I could not get yesterdays and now it seems so obvious! lol.

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  5. Colour me mindfucked. I've just woken up, too early for this XD

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  6. Uh, this one is difficult. Tried something but it didn't work, ended up having 5|7. :/

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  7. I'm going to take a guess, and I can't really explain out why, but I would count out a pile of thirteen cards and flip them over. Then, leave the rest.

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  8. Nice one!!!
    http://fassionsanne.blogspot.com/

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  9. Hmm, don't get this one, nor can I come up with a witty half answer.

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  10. Eat 50 cards.
    Put each remaining card in separate deck.
    Pray to God.

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  11. Take 13 cards off the top of the deck and flip them over to make one pile and the rest of the deck is the other :)

    You should probably have changed the number of face up cards in the deck to an even number because the solution is too obvious with an odd one :)

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  12. Not easy! :D But gonna follow you. This is like a daily braintraining! :D

    http://pokeretc.blogspot.com/

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  13. If the cards have been preshuffled THEN the cards were put face up, the face up cards should feel different and are therefore sortable.

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  14. i can do this trick without a blindfold

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  15. I... don't know but it's a nice puzzle :P

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  16. This one's tough. I would split the cards up into two equal sized piles and hope for the best.

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  17. This one is great. Maybe this helps mathematicly. (I can't put it in one equation) : There is total of 13 FO (flip over) cards. So when we select 13 random cards the number of FO cards is X (Range:0-13). In the rest of the cards (39) there is now 13-x FO cards left. So basically by flipping over your 13 cards pile here are now 13-x FO cards too. Hope you can understand what I am talking about.

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  18. OH MAN I NEVER GET ANYTHING RIGHT

    Brb suicide

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