Posers and Puzzles

Posers and Puzzles

  1. Joined
    29 Dec '08
    Moves
    6788
    06 Apr '16 07:123 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. Joined
    29 Dec '08
    Moves
    6788
    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. SubscriberAThousandYoung
    iViva la Hispanidad!
    tinyurl.com/y2c6j2t3
    Joined
    23 Aug '04
    Moves
    24791
    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 memberapathist
    looking for loot
    western colorado
    Joined
    05 Feb '11
    Moves
    9664
    07 Apr '16 17:113 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 memberapathist
    looking for loot
    western colorado
    Joined
    05 Feb '11
    Moves
    9664
    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 memberwolfgang59
    Mr. Wolf
    at home
    Joined
    09 Jun '07
    Moves
    46058
    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 memberwolfgang59
    Mr. Wolf
    at home
    Joined
    09 Jun '07
    Moves
    46058
    09 Apr '16 23:432 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. San Francisco, CA US
    Joined
    09 Jan '07
    Moves
    125198
    09 May '16 05:56
    0%. There is no guarantee any of the answers are correct.
  9. Standard memberwolfgang59
    Mr. Wolf
    at home
    Joined
    09 Jun '07
    Moves
    46058
    09 May '16 20:39
    Originally posted by ParShooter
    0%. There is no guarantee any of the answers are correct.
    Show your working..............
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