Blind card sorting puzzle – the answer

27 Jan

Here is another puzzle that I never got round to answering… Until today. Firstly, here is the puzzle again:

“A blind person is given a normal deck of 52 cards. They are told that exactly 10 of the cards are facing up, all the rest are facing down. How can the blind person divide the cards into 2 separate piles, with each pile consisting of an equal number of cards facing up?”

The answer is below

Take the top 10 cards of the deck and put them in a separate pile to the remaining 42 cards. Turn all of the 10 cards over. Now both piles will consist of an equal number of cards facing up.

If all of the 10 cards remove from the deck were originally face-up, turning them over will result in both piles containing 0 face-up cards. If none of the 10 cards remove from the deck were originally face-up, turning them over will result in both piles containing 10 face-up cards. The same is true if just some of the 10 cards remove from the deck were originally face-up… both piles will contain the same number of face-up cards

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6 Responses to “Blind card sorting puzzle – the answer”

  1. postadaychallenge2011 January 27, 2011 at 3:09 am #

    I enjoyed this “10 cards riddle or puzzle.” Thought provoking questions I like to ponder and see. Keep up the great work on this blog, I love your background.

    • stickinsect January 30, 2011 at 10:06 pm #

      Thanks, I made the background myself in paint.net. I wanted something that looks unique.

  2. Sandra Bell Kirchman January 27, 2011 at 5:56 am #

    Good one, Michael. It had me stumped, but then I’m not very good at these puzzles. I do enjoy them and especially the clever answers.

    Sandra
    Wizards and Ogres and Elves…oh my!

    • stickinsect January 30, 2011 at 10:08 pm #

      Yeah, I really enjoy clever puzzles that do not simply involve crude tricks.

  3. misspinkles January 28, 2011 at 12:26 pm #

    nice one!

    • stickinsect January 30, 2011 at 10:55 pm #

      Glad you liked it. Thanks for visiting.

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