Posers and Puzzles

Posers and Puzzles

  1. Joined
    11 Jun '06
    Moves
    3516
    06 Jul '06 01:57
    you are blindfolded ad then 100 coins are placed on a table in front of you. 7 are showing heads and 93 show tails.
    You may flip coins or sort coins, how do you create two (not necessarily equal) piles such that each pile has the same number of heads showing. (no feeling the coin to see which side its on; this is a strictly mathamatical puzzle)
  2. Joined
    21 Sep '05
    Moves
    75006
    06 Jul '06 06:59
    Originally posted by aginis
    you are blindfolded ad then 100 coins are placed on a table in front of you. 7 are showing heads and 93 show tails.
    You may flip coins or sort coins, how do you create two (not necessarily equal) piles such that each pile has the same number of heads showing. (no feeling the coin to see which side its on; this is a strictly mathamatical puzzle)
    Choose any 7 of the coins and slide them carefully to make a second pile (the other 93 constitute the first pile). Turn the 7 coins over. Ta-da!
    [If the 7 coins were all tails then there are 7 heads in pile 1 and you have made 7 heads in pile 2 when you turned them over. If there were 2 heads in the 7 you chose then when you turn them over you get 5 heads ... the same as there are in pile 1. Etc]

    I like this puzzle because there is no computer program needed (too much hassle to bother with!) and at first glance it appears that there is not enough information to solve it.

    [Also - anyone know why when I type an apostrophe in this box (browser = Firefox) it opens a "find" pane?]
  3. Joined
    11 Jun '06
    Moves
    3516
    06 Jul '06 08:48
    Originally posted by Diapason
    Choose any 7 of the coins and slide them carefully to make a second pile (the other 93 constitute the first pile). Turn the 7 coins over. Ta-da!
    [If the 7 coins were all tails then there are 7 heads in pile 1 and you have made 7 heads in pile 2 when you turned them over. If there were 2 heads in the 7 you chose then when you turn them over you get 5 hea ...[text shortened]... ne know why when I type an apostrophe in this box (browser = Firefox) it opens a "find" pane?]
    good job now one for all those program lovers same question only now
    10^17 coins and 38478 are heads. how do you do it?
  4. SubscriberAThousandYoung
    iViva la Hispanidad!
    tinyurl.com/y2c6j2t3
    Joined
    23 Aug '04
    Moves
    24791
    06 Jul '06 12:14
    Originally posted by aginis
    good job now one for all those program lovers same question only now
    10^17 coins and 38478 are heads. how do you do it?
    Take 38478 out of the pile and flip them all over?
  5. Joined
    11 Jun '06
    Moves
    3516
    06 Jul '06 13:58
    Originally posted by AThousandYoung
    Take 38478 out of the pile and flip them all over?
    😀
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