Posers and Puzzles

Posers and Puzzles

  1. Joined
    08 Dec '06
    Moves
    23599
    09 Apr '19 02:211 edit
    My friend sent me this:
    "There are 42 coins on a table. Of those, 10 are heads-up and the other 32 are tails-up.

    How can you separate the coins into two groups so that each contains the same number of coins that are heads-up?

    Note that you cannot see nor feel the coins, though you can manipulate them. (you are blindfolded and wearing gloves)."

    I solved it and proved that my solution is correct. I'm interested in seeing if other solutions exist.
  2. Standard memberforkedknight
    Defend the Universe
    127.0.0.1
    Joined
    18 Dec '03
    Moves
    16104
    09 Apr '19 02:424 edits
    @damionhonegan said
    My friend sent me this:
    "There are 42 coins on a table. Of those, 10 are heads-up and the other 32 are tails-up.

    How can you separate the coins into two groups so that each contains the same number of coins that are heads-up?

    Note that you cannot see nor feel the coins, though you can manipulate them. (you are blindfolded and wearing gloves)."

    I solved it and proved that my solution is correct. I'm interested in seeing if other solutions exist.
    Reveal Hidden Content
    Take 10 coins from the pile of 42 and move them into a separate pile. Flip all 10 of those over.


    Reveal Hidden Content
    If you happen to pick all 10 of the heads-up coins, both piles have 0. If you pick n of the head-up coins, both piles will have 10-n
  3. Joined
    08 Dec '06
    Moves
    23599
    09 Apr '19 03:471 edit
    @forkedknight
    This is my solution. Are there any other?
  4. Joined
    26 Apr '03
    Moves
    26099
    14 Apr '19 09:22
    @damionhonegan said
    This is my solution. Are there any other?
    Put 32 coins into a new pile and flip the ten coins left in the other pile.
  5. SubscriberAThousandYoung
    iEn guardia, Ingles!
    tinyurl.com/y43jqfyd
    Joined
    23 Aug '04
    Moves
    24791
    15 Apr '19 20:22
    Put all the coins on the edge.
Back to Top