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Thread: I need the real answer to this problem.

  1. #1
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    I need the real answer to this problem.

    Was asked this question online.

    If you choose an answer to this question at random what is the chance you will be correct?

    a) 25%
    B) 50%
    C) 60%
    D) 25%

    My answer was...

    1. If A=D then the answer is 33%
    2. If A does not =D (A and D are not similar objects like ingredients to a fruit salad) Then the answer is 25%

    With both being possible here are my thoughts.

    So what I did is I took 33% - 25% and got 8% and divided it evenly across all 4 answer and got 2% and added it to the 25% and got 27% as my answer.

    I was told I was wrong. If I am wrong please explain how I am wrong.
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  2. #2
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    Re: I need the real answer to this problem.

    P[correct answer] = (1/4+1/4)(1/3) + (1/4)(1/3)+(1/4)(1/3) = 1/6 + 1/12 + 1/12 = 1/3 = 33.33..%

    you have to assume that 25% is 25% and there is no distinction between the two occurences.
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  3. #3
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    Re: I need the real answer to this problem.

    I disagree with both of those answers.
    IF the answer was 27% (or 33.33% for that matter) then you would be 100% incorrect if you chose an answer from those options.
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  4. #4
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    Re: I need the real answer to this problem.

    Quote Originally Posted by Skyrivers View Post
    If you choose an answer to this question at random what is the chance you will be correct?
    a) 25% B) 50% C) 60% D) 25%
    So what I did is I took 33% - 25% and got 8% and divided it evenly across all 4 answer and got 2% and added it to the 25% and got 27% as my answer. I was told I was wrong. If I am wrong please explain how I am wrong.
    Suppose the question were:
    $2+3=\;A)\;5\quad B)\;4\quad C)\;3\quad D)\;5$

    Now ask, " If a student randomly marks an answer, then what is the probability of its being correct?"
    What would be your answer?

    Is there any difference this and the question you posted?
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  5. #5
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    Re: I need the real answer to this problem.

    Quote Originally Posted by Plato View Post
    Suppose the question were:
    $2+3=\;A)\;5\quad B)\;4\quad C)\;3\quad D)\;5$

    Now ask, " If a student randomly marks an answer, then what is the probability of its being correct?"
    What would be your answer?

    Is there any difference this and the question you posted?
    The answer to Plato's question is 50% because 2 of the 4 answers are correct.

    But the original question was "If you choose an answer to THIS question at random what is the chance you will be correct?

    a) 25%
    B) 50%
    C) 60%
    D) 25%"

    THIS question is this question, not some other question. They are totally different.
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  6. #6
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    Re: I need the real answer to this problem.

    Quote Originally Posted by Debsta View Post
    But the original question was "If you choose an answer to THIS question at random what is the chance you will be correct?
    a) 25%
    B) 50%
    C) 60%
    D) 25%"
    THIS question is this question, not some other question. They are totally different.
    No they are not different. They are exactly the same question.
    Like $5$ in the question I posed, $25\%$ serves the exact same role.
    The question is "What is the probability that a randomly chosen response is correct?"
    Here is the OP.
    Quote Originally Posted by Skyrivers View Post
    If you choose an answer to this question at random what is the chance you will be correct?
    a) 25% B) 50% C) 60% D) 25%
    Now regardless of the distractors, if there are four different ones then then there is a $25\%$ chance of being correct if one is correct.
    If as in this example (& mine) there are two correct options, then the correct answer to the question "What is the probability of a random correct answer?" is $50\%$.
    In other words, this is a question about careful reading. You failed it.
    This question has been given to several generations of hopeful editors.
    I will admit that in this form there is a self-reference that I have never seen.
    But that does not change the object of the question.
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  7. #7
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    Re: I need the real answer to this problem.

    But, if the answer is 50%, as you state, then the solution is B and the chance of a random correct answer is only 25%.

    The self-reference makes the question ill-defined.
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  8. #8
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    Re: I need the real answer to this problem.

    Quote Originally Posted by Plato View Post
    No they are not different. They are exactly the same question.
    Like $5$ in the question I posed, $25\%$ serves the exact same role.
    The question is "What is the probability that a randomly chosen response is correct?"
    Here is the OP.

    Now regardless of the distractors, if there are four different ones then then there is a $25\%$ chance of being correct if one is correct.
    If as in this example (& mine) there are two correct options, then the correct answer to the question "What is the probability of a random correct answer?" is $50\%$.
    In other words, this is a question about careful reading. You failed it.
    This question has been given to several generations of hopeful editors.
    I will admit that in this form there is a self-reference that I have never seen.
    But that does not change the object of the question.
    No no, no.

    Here's a question for you Plato (in almost your own words):

    Suppose the question were:
    2+4= A)5 B)4 C)3 D)5

    Now ask, " If a student randomly marks an answer, then what is the probability of its being correct?"
    What would be your answer?
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  9. #9
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    Re: I need the real answer to this problem.

    Quote Originally Posted by Plato View Post
    No they are not different. They are exactly the same question.
    Like $5$ in the question I posed, $25\%$ serves the exact same role.
    The question is "What is the probability that a randomly chosen response is correct?"
    Here is the OP.

    Now regardless of the distractors, if there are four different ones then then there is a $25\%$ chance of being correct if one is correct.
    If as in this example (& mine) there are two correct options, then the correct answer to the question "What is the probability of a random correct answer?" is $50\%$.
    In other words, this is a question about careful reading. You failed it.
    This question has been given to several generations of hopeful editors.
    I will admit that in this form there is a self-reference that I have never seen.
    But that does not change the object of the question.
    Also,
    If 50% is the correct answer, ie B is the correct answer, the probability of choosing B (the correct answer according to Plato) is 25%, so 50% is incorrect.
    Thanks from SlipEternal
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