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Math Help - which two numbers do not belong in here?

  1. #1
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    which two numbers do not belong in here?

    hi there, anybody can help solve this? , TQ.

    4--------- 2--------- 8
    17-------- 54 --------92
    298 ------756------- 644
    2134 ----5196------ 8843


    The question is: Out of the 12 numbers in the 3x4 box (the 12 numbers each in one square) up there, Which 2 numbers do not belong up there?
    Last edited by labrador007; April 27th 2011 at 11:39 PM. Reason: clarification
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  2. #2
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    Well, not knowing what this is, like trick, puzzle, math related,
    then I can say: 644 and 8842; only 2 numbers with 2 repeated digits
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    thanks wilmer for your reply.

    seriously i dont know the answer, i wonder if there is any other .

    but my answer is 17 and 8843.
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    Quote Originally Posted by labrador007 View Post
    thanks wilmer for your reply.
    seriously i dont know the answer, i wonder if there is any other .
    but my answer is 17 and 8843.
    I think there are \dbinom{12}{2}=66 correct answers.
    I can justify each of those 66 answers.
    This is a nonsense question.
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    Quote Originally Posted by labrador007 View Post
    seriously i dont know the answer, i wonder if there is any other .
    but my answer is 17 and 8843.
    OK; say that's the answer: only 2 odd numbers: so, what's been achieved?
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    It was just a question from my son's IQ Maths which he asked me.

    As i am not sure if my answer is correct i ask for opinion here.

    However, I cannot fathom how there can be 66 answers all with logical reasoning.
    Last edited by topsquark; April 28th 2011 at 04:41 AM. Reason: Somewhat insulting comment
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    Quote Originally Posted by labrador007 View Post
    It was just a question from my son's IQ Maths which he asked me.

    As i am not sure if my answer is correct i ask for opinion here.

    However, I cannot fathom how there can be 66 answers all with logical reasoning.
    The point that Plato is making is that we can potentially pick any two of the numbers and find some sort of reasoning to say they are different from the rest. It is a similar concept to having a list of numbers, say 1, 2, 4, 5, 7 and ask what the next number is. If you are sufficiently clever you can argue that any number is the next in the series.

    So there really is no "right" or "wrong" answer to your question. The question itself is flawed.

    -Dan
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    for some lunatic reason i thought 17, 8843 on the grounds that they were the only prime numbers before noticing that they were also the only odd numbers.

    Im not a psychiatrist but i think you need to be careful before discarding this sort of thing as a rubbish test/stupid question. I agree that any sufficiently clever person could come up with a justification for any of the pairs, and so the question isn't perfect (especially if only 1 answer will get any credit).

    However the purpose of IQ testing is to predict certain traits (i dont know what they are, but anyway), so the only issue of relevance to the tester is whether or not there is a correlation between certain answers and the traits being tested for. If its a professional test i would assume they tested for that correlation when designing the answer key.
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    Quote Originally Posted by SpringFan25 View Post
    for some lunatic reason i thought 17, 8843 on the grounds that they were the only prime numbers before noticing that they were also the only odd numbers.

    Im not a psychiatrist but i think you need to be careful before discarding this sort of thing as a rubbish test/stupid question. I agree that any sufficiently clever person could come up with a justification for any of the pairs, and so the question isn't perfect (especially if only 1 answer will get any credit).

    However the purpose of IQ testing is to predict certain traits (i dont know what they are, but anyway), so the only issue of relevance to the tester is whether or not there is a correlation between certain answers and the traits being tested for. If its a professional test i would assume they tested for that correlation when designing the answer key.
    So long as any sets of answers are tested based on the reasoning leading to them as opposed to the answer key having one specific answer then I agree with you.

    -Dan
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    Quote Originally Posted by SpringFan25 View Post
    for some lunatic reason i thought 17, 8843 on the grounds that they were the only prime numbers before noticing that they were also the only odd numbers.
    They are not the only prime numbers in the array.

    CB
    Last edited by CaptainBlack; April 28th 2011 at 05:45 AM.
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    Quote Originally Posted by labrador007 View Post
    hi there, anybody can help solve this? , TQ.

    4--------- 2--------- 8
    17-------- 54 --------92
    298 ------756------- 644
    2134 ----5196------ 8843


    The question is: Out of the 12 numbers in the 3x4 box (the 12 numbers each in one square) up there, Which 2 numbers do not belong up there?
    There are only two that are divisible by 14.
    There are only two that are divisible by 12.
    There are only two that are divisible by 9.
    There are only two that are divisible by 7 (the same two as divisible by 14).

    There are only two semi-primes.

    There are only two with four neighbours.

    etc

    CB
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  12. #12
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    Quote Originally Posted by CaptainBlack View Post
    They are not the only prime numbers in the array.

    CB
    Exactly. SpringFan25 has overlooked the number 2. May be he did this because those are the only two odd numbers and it is only the odd numbers which can be prime (apart from 2,of course). So I think may be he too first noticed that those numbers were odd....gusess whatsoever.....
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    8843 isn't prime, so my post was a bit of a mess. What i meant to say was i thought about "2,17" as prime before noticing "17, 8843" as odd. Which i think is pretty lunatic of me...


    However the purpose of my post was not to say "hey, this is the answer" it was that having many answers doesn't make it a bad question, provided the answer key has been done sensibly, to give credit to those answers which correlate best to what IQ tests are looking for.
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    Quote Originally Posted by labrador007 View Post
    hi there, anybody can help solve this? , TQ.

    4--------- 2--------- 8
    17-------- 54 --------92
    298 ------756------- 644
    2134 ----5196------ 8843


    The question is: Out of the 12 numbers in the 3x4 box (the 12 numbers each in one square) up there, Which 2 numbers do not belong up there?
    While we are at it 2 and 8843 are the only two numbers that add up to 8845...

    -Dan
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    Quote Originally Posted by labrador007 View Post
    hi there, anybody can help solve this? , TQ.

    4--------- 2--------- 8
    17-------- 54 --------92
    298 ------756------- 644
    2134 ----5196------ 8843


    The question is: Out of the 12 numbers in the 3x4 box (the 12 numbers each in one square) up there, Which 2 numbers do not belong up there?
    Another simple pattern,
    all depending on the level of the child being tested,
    is that...
    the numbers are increasing from the previous one
    except for "2" and "644".

    If it weren't for those,
    the first line could be increasing in units,
    the 2nd line increasing in tens,
    the third line increasing in hundreds,
    the fourth line increasing in thousands,

    or just take the sequence beginning with 4 and ending with 8843.
    Last edited by Archie Meade; April 28th 2011 at 10:11 AM.
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