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Missing #

  1. Nov 23, 2009 #1
    What's the missing number and why?

    http://img18.imageshack.us/img18/2408/a89raetsel.png [Broken]​
    [/URL]
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Nov 23, 2009 #2

    drizzle

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    5 [and this just to submit the post, damn 4 characters! :grumpy:]
     
  4. Nov 23, 2009 #3
    why?
     
  5. Nov 23, 2009 #4

    drizzle

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    21
    23
    25
    27
     
  6. Nov 23, 2009 #5
    I thought that too, but you beat me to it. You don't think there might be a pattern in the columns?
     
  7. Nov 23, 2009 #6

    drizzle

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    24 22 22 28 :biggrin:

    hold on a sec!
     
  8. Nov 23, 2009 #7

    drizzle

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    1st sum [raw]= 1st sum [column]-3
    2nd sum [raw]= 2nd sum [column]+1
    3rd sum [raw]= 3rd sum [column]+3
    4th sum [raw]= 4th sum [column]-1

    so :rolleyes:
     
  9. Nov 24, 2009 #8
    I guess that works. But this puzzle could have more than one answer. When you add all of the number up you get 91. So the ? could be a 9, making the total a perfect square :biggrin:
     
  10. Nov 25, 2009 #9
    Another (and stupid) way to get 5:

    Each row and column has two numbers that have 4 letters, hence the missing number must have 4 letters. Each row has an odd number of odd values, and each column has an even number of odd values. Hence, the missing number must be odd. The only choices being 5 or 9. Looking at the rows, no number is more than 3 away from its neighbors, hence, the number cannot be 9, and must be 5.

    DaveE
     
  11. Nov 28, 2009 #10
    What about 4?

    Look at the total for each column and each row.

    Column 1: 24
    Column 2: 23
    Column 3: ?
    Column 4: 27

    Row 1: 21
    Row 2: 23
    Row 3: ?
    Row 4: 27

    If you use 4, that means the 3rd row is 24 and the 3rd column is 21. Therefore there is a 1:1 ratio of the frequency of column sums to row sums.

    ..right?
     
  12. Nov 28, 2009 #11

    drizzle

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    check it :)
     
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