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Goldiolics (Posted on 2018-03-30) Difficulty: 3 of 5
Charlie has 128 identical-looking gold-colored coins; all are counterfeit except one.

He calls Alice into his office and seats her at a table containing two 8 × 8 boards, with a coin on each of the 128 squares, each coin showing a head or tail as he chooses.

He tells Alice which coin is made of gold. Alice can then turn at most 4 coins upside down, replacing them on their squares, but her inversions must all be on the first row of the left-hand board. She then leaves the room.

Bob enters and is seated in the same position, facing the boards. He may take one of the 128 coins.

Find a strategy that allows Bob to always take the gold coin.

Alice and Bob know the protocol in advance and can plan a strategy, but cannot communicate after Alice enters the room.

No Solution Yet Submitted by Danish Ahmed Khan    
Rating: 5.0000 (1 votes)

Comments: ( You must be logged in to post comments.)
  Subject Author Date
Buy CBD vape oilcheapkamagra2018-04-03 03:13:10
re(3): one possible strategyDej Mar2018-03-31 07:24:41
re(2): one possible strategyarmando2018-03-31 03:26:21
re(2): one possible strategybroll2018-03-31 02:53:21
Some Thoughtsre: one possible strategyDej Mar2018-03-31 00:11:01
one possible strategyarmando2018-03-30 09:48:37
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