2 piles of 100 coins puzzle

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You have 100 coins laying flat on a table, each with a head side and a tail side. 10 of them are heads up, 90 are tails up.
You can’t feel, see or in any other way find out which side is up.

Split the coins into two piles such that there are the same number of heads in each pile.

How did you do it?

 

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SherlockHolmes Expert Asked on 22nd September 2015 in Interview Puzzles.
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  • 1 Answer(s)

    SOLUTION-
    “Split into two piles, one with 90 coins and the other with 10.  Flip over every coin in the pile with 10 coins.

    EXPLANATION-
    I will select 10 Coins and out which I would have X number of heads, where X can be between 0 to 10.
    So I would be left with 10-X number of Heads in the original group.
    And then I flip them, which makes the number of heads in both groups equal.

    OTHER QUITE INTERESTING SOLUTION-
    Split them in piles of 50-50..as each coin has head and tail on either side and the question asks for 2 piles of equal no. of heads.
    Note- HEADS and HEADS UP are different 😛

    Detective Expert Answered on 23rd September 2015.
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