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Get them up (Posted on 2014-10-01) Difficulty: 2 of 5
10 playing cards are placed face-down on a table, forming a circle.
Your are allowed to turn over simultaneously 4 cards that either:
a.)all 4 are consecutive,
b.) 2 are on the left and 2 on the right of any specific card chosen by you (i.e. out of 5 consecutive cards only the middle one remains unturned) .

By executing a final number of the above (a. or b.) procedures can you reach an "all face-up" state?

If yes, explain how.
Otherwise, prove why not.

No Solution Yet Submitted by Ady TZIDON    
Rating: 4.0000 (1 votes)

Comments: ( You must be logged in to post comments.)
  Subject Author Date
re(2): Unsatisfying computer proofCharlie2014-10-02 10:53:50
Satisfying indeed.xdog2014-10-02 10:25:29
re: Unsatisfying computer proofSteve Herman2014-10-02 10:22:56
SolutionSatisfying analytical proof (spoiler)Steve Herman2014-10-02 08:45:26
SolutionUnsatisfying computer proofCharlie2014-10-01 11:21:11
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