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Puzzle 2nd November 05

 
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Bigdad



Joined: 02 Nov 2005
Posts: 2

PostPosted: Wed Nov 02, 2005 4:10 pm    Post subject: Puzzle 2nd November 05 Reply with quote

I'm really stuck on todays. I've got as far as

48x 3xx xxx
9x7 452 x8x
xx3 1x8 74x

8x5 713 4xx
7xx 946 Xx8
x49 825 1x7

x94 581 27x
17x 234 xx5
xxx 6xx x14

I asked for a hint and the capital X above was given as 5. I would be grateful if someone could tell me why!!


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David Bryant



Joined: 29 Jul 2005
Posts: 559
Location: Denver, Colorado

PostPosted: Wed Nov 02, 2005 4:40 pm    Post subject: Why is it a "5"? Reply with quote

Hi, Bigdad! Welcome to the forum.

The answer lies in column 8. If you examine column 8 carefully you will see that the only way a "3" can fit in that column is if it goes in r5c8 or r6c8. In other words, the "3" in the middle right 3x3 box must lie in column 8.

The only values possible at r5c7 are {3, 5}. But that cell can't contain a "3" because of the column 8 situation, so it must be a "5". dcb
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PostPosted: Wed Nov 02, 2005 5:06 pm    Post subject: Still stuck Reply with quote

HI-

OK, i am in the same place as Bigdad. I now see why 5 was given as a hint (thank you)- but I am new to sudoku and I still cant solve this puzzle. I am at the exact same place as Bigdad, and I dont understand x-wing, xy-wing, or any other method to solve tough puzzles. Please help!

Thanks,

~Courtney~
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David Bryant



Joined: 29 Jul 2005
Posts: 559
Location: Denver, Colorado

PostPosted: Wed Nov 02, 2005 5:38 pm    Post subject: The next step after Bigdad's "5" Reply with quote

OK, Courtney, here's a little more help for you.

I suppose you have already placed the "5" at r5c1 and then at r1c8 -- the second move is immediately obvious.

Now look at row 1. Samgj has very cleverly hidden the pair {1, 2} in this row. The way to spot this is to look at the five open spots in row 1 (r1c3, r1c5, r1c6, r1c7, & r1c9). The pair {1, 2} already appears in columns 5, 6, and 7. So the only way the values {1, 2} can fit in the first row is at r1c3 & at r1c9.

Now you have the {1, 2} pair appearing in column 3, allowing you to fill in r8c3 and r9c3 immediately. dcb
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PostPosted: Wed Nov 02, 2005 6:31 pm    Post subject: Reply with quote

Thank you! I am beggining to see all the fun little tricks in this game

~Courtney~
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