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Probability Problem

Posted By: poseidon
Date: Thursday, 27 August 2009, at 1:26 p.m.

Here is a controversial probability problem I found on the net:

"Remove all the cards except aces and kings from a deck. From this, deal two cards to a friend. If she looks at her cards and announces (truthfully) that her hand contains an ace, what is the probability that both her cards are aces? If she announces instead that one of her cards is the ace of spades, what is the probability then that both her cards are aces?"

It is said that it has been in controversy even amongst the elite of probability theorists.

Messages In This Thread

• Probability Problem
  poseidon -- Thursday, 27 August 2009, at 1:26 p.m.
  • Probability Problem
    misja -- Thursday, 27 August 2009, at 1:42 p.m.
    • Probability Problem
      Stick -- Thursday, 27 August 2009, at 3:31 p.m.
    • Probability Problem
      Petter Bengtsson -- Thursday, 27 August 2009, at 3:46 p.m.
  • Probability Problem
    Gregg Cattanach -- Thursday, 27 August 2009, at 3:49 p.m.
    • Probability Problem
      Bob Koca -- Thursday, 27 August 2009, at 4:19 p.m.
    • Probability Problem
      Chuck Bower -- Thursday, 27 August 2009, at 4:46 p.m.
    • Probability Problem
      Jason Lee -- Thursday, 27 August 2009, at 7:54 p.m.
  • Probability Problem
    Neil Robins -- Thursday, 27 August 2009, at 4:14 p.m.
    • Probability Problem
      Gregg Cattanach -- Thursday, 27 August 2009, at 5:37 p.m.
      • Probability Problem
        Bob Koca -- Thursday, 27 August 2009, at 5:56 p.m.
        • Probability Problem
          Gregg Cattanach -- Thursday, 27 August 2009, at 6:07 p.m.
          • Probability Problem
            Bob Koca -- Thursday, 27 August 2009, at 7:42 p.m.
            • Probability Problem
              Gregg Cattanach -- Thursday, 27 August 2009, at 8:09 p.m.
              • Probability Problem
                joe freedman -- Thursday, 27 August 2009, at 8:26 p.m.
                • Probability Problem
                  poseidon -- Thursday, 27 August 2009, at 8:37 p.m.
                • Probability Problem
                  Jason Lee -- Thursday, 27 August 2009, at 8:47 p.m.
              • Probability Problem
                Gregg Cattanach -- Friday, 28 August 2009, at 1:58 a.m.
                • Probability Problem
                  Paul Vianna -- Friday, 28 August 2009, at 2:11 a.m.
                  • Probability Problem
                    Chuck Bower -- Friday, 28 August 2009, at 4:06 p.m.
            • monte hall called this
              garyo -- Saturday, 29 August 2009, at 7:51 a.m.
  • Probability Problem
    Chuck Bower -- Thursday, 27 August 2009, at 5:16 p.m.
  • Probability Problem
    Timothy Chow -- Thursday, 27 August 2009, at 6:03 p.m.
    • Probability Problem
      Bob Koca -- Thursday, 27 August 2009, at 6:06 p.m.
      • Probability Problem
        poseidon -- Thursday, 27 August 2009, at 6:18 p.m.
  • Probability Problem
    joe freedman -- Thursday, 27 August 2009, at 6:35 p.m.
    • Probability Problem
      joe freedman -- Thursday, 27 August 2009, at 6:39 p.m.
  • Probability Problem
    Jason Lee -- Thursday, 27 August 2009, at 7:57 p.m.
  • Probability Problem
    Bob Koca -- Friday, 28 August 2009, at 2:13 a.m.
    • Probability Problem
      poseidon -- Friday, 28 August 2009, at 10:29 a.m.