Brain Teasers
Naughts & Crosses
Sally and Sully are playing a special version of naughts and crosses. They must each draw up a naughts and crosses board with every square filled with either a naught (O) or a cross (X). Then they must each give clues and the other person had to guess the exact placings of the X's and the O's.
It is Sally's turn and Sully is giving clues. Can you figure it out for Sally?
NOTE: It is a standard naughts and crosses board, so it will be like this.
? ? ?
? ? ?
? ? ?
Or a coordinate version:
1,1 2,1 3,1
1,2 2,2 3,2
1,3 2,3 3,3
Ok, let's get started.
_____________________________
1. There is an O in the very middle (2,2).
2. There are three X's surrounding the middle square (not including diagonals).
3. There are 4 X's and 5 O's on the board.
4. The bottom right square (3,3) contains an X.
5. There is not an X on the bottom row in the middle (2,3).
It is Sally's turn and Sully is giving clues. Can you figure it out for Sally?
NOTE: It is a standard naughts and crosses board, so it will be like this.
? ? ?
? ? ?
? ? ?
Or a coordinate version:
1,1 2,1 3,1
1,2 2,2 3,2
1,3 2,3 3,3
Ok, let's get started.
_____________________________
1. There is an O in the very middle (2,2).
2. There are three X's surrounding the middle square (not including diagonals).
3. There are 4 X's and 5 O's on the board.
4. The bottom right square (3,3) contains an X.
5. There is not an X on the bottom row in the middle (2,3).
Hint
Go ahead - draw up a naughts and crosses board!Answer
The board should look like this.O X O
X O X
O O X
After the first clue, all you know is that O is in the middle.
? ? ?
? O ?
? ? ?
At this point, clues 2 and 3 are useless.
Clue 4 says that the bottom right square contains an X.
Now your board should look like this:
? ? ?
? O ?
? ? X
Clue 5 says there is no X at 2,3.
The board should look like this:
? ? ?
? O ?
? O X
Now you can come back to clue 2.
Since there are three X's surrounding the middle square (no diagonals, the X's must go in these three places:
? X ?
X O X
? O X
Clue 3 says that there are only 4 X's on the board - there are 4 X's on the board at that point so the rest must be O's.
O X O
X O X
O O X
So - Sally ended up winning, because she found out the placings of Sully's board in lightning quick speed thanks to you! Way to go!
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Comments
IMHO this is the same as tic-tac-toe. Same format and layout.
Yay i got it!
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