Please turn on javascript in your browser to play chess.
Posers and Puzzles

Posers and Puzzles

  1. 06 Apr '16 07:12 / 3 edits
    If you choose one of the following answers to this question at random, what are the chances you will be correct?
    A) 25%
    B) 50%
    C) 33.3333...%
    D) 25%

    Please explain why your answer is correct.
  2. 06 Apr '16 16:49
    Originally posted by JS357
    If you choose one of the following answers to this question at random, what are the chances you will be correct?
    A) 25%
    B) 50%
    C) 33.3333...%
    D) 25%

    Please explain why your answer is correct.
    Note: There are links to discussion of this poser at

    http://blog.tanyakhovanova.com/2011/11/a-probabilistic-paradox/
  3. Subscriber AThousandYoung
    Proud Boys Beware
    06 Apr '16 19:59
    Originally posted by JS357
    If you choose one of the following answers to this question at random, what are the chances you will be correct?
    A) 25%
    B) 50%
    C) 33.3333...%
    D) 25%

    Please explain why your answer is correct.
    B because A and D
  4. Standard member apathist
    looking for loot
    07 Apr '16 17:11 / 3 edits
    Since the percent values listed aren't relevant, I get rid of the confusion they offer by substitution like this:

    a) x
    b) y
    c) z
    d) x

    ..actual answer
    ....x..y..z
    .a 1 0 0 = 1/3
    .b 0 1 0 = 1/3
    .c 0 0 1 = 1/3
    .d 1 0 0 = 1/3

    Okay, that's a matrix, with the columns labeled (x,y,z) and the rows (a,b,c,d).
    The first column assumes x is the correct answer, and each row under that column shows what happens when x is correct. Do the same then for each column.
    Total each row. They all add up to 1 chance out of 3 tries to guess the correct answer.

    I guess the answer is 1/3.

    I keep thinking that because one answer appears twice, that should affect the odds. But it seems that no matter which of the three possible answers is correct, and no matter which of the four possible choices I select, my chances of choosing the correct answer are 1 out of 3. Probability is not very intuitive.

    Now I wanna go see that discussion link.
  5. Standard member apathist
    looking for loot
    07 Apr '16 17:23
    Shoot, I didn't understand the question. It's a self-referential paradox, not an arbitrary and unstated question as I assumed.
  6. Standard member wolfgang59
    Infidel
    08 Apr '16 11:34
    Originally posted by JS357
    If you choose one of the following answers to this question at random, what are the chances you will be correct?
    A) 25%
    B) 50%
    C) 33.3333...%
    D) 25%

    Please explain why your answer is correct.
    E.
    Try Google.
  7. Standard member wolfgang59
    Infidel
    09 Apr '16 23:43 / 2 edits
    Originally posted by JS357
    If you choose one of the following answers to this question at random, what are the chances you will be correct?
    A) 25%
    B) 50%
    C) 33.3333...%
    D) 25%

    Please explain why your answer is correct.
    It depends how we "choose at random".
    If we randomly choose from (A, B, C, D) then there is no solution.

    However if we randomly choose from the available answers
    (25%, 33.3%, 50% ) then the answer is C. 33.3%

    So in a written test I'd go for 'C'
    On a chess forum I'd plump for
  8. 09 May '16 05:56
    0%. There is no guarantee any of the answers are correct.
  9. Standard member wolfgang59
    Infidel
    09 May '16 20:39
    Originally posted by ParShooter
    0%. There is no guarantee any of the answers are correct.
    Show your working..............