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Quiz Master’s Master Quiz Watch

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    (Original post by Quiz Master)
    The strategy was one of them would say the result of their coin toss (so if the toss was heads, they would predict the other coin toss was the same), while the other person would predict that the coin toss was different.

    This way they are guaranteed to survive an extra day

    QM
    I'm still lost.:confused:

    So if A always said the same as their toss.
    And B always said different.

    Then if A = heads = heads
    and B = heads = tails

    and if A = heads = heads
    and B = tails = heads

    and if A = tails = tails
    and B = heads = tails

    then A = tails = tails
    and B = tails = heads

    EDIT:
    (Original post by Quiz Master)
    Every day a guard will come in to their dungeon and flip a coin. Alice and Bob must then guess what the result of the other person’s coin flip was. If either of them guess correctly, they will live for another day.
    Oh I see. I hadn't realised that they meant both of them here. Thought it was just one.
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    (Original post by 04MR17)
    Oh I see. I hadn't realised that they meant both of them here. Thought it was just one.
    Yes, if either of them guess correctly, they both live.

    QM
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    Question 2: you are in the dark, and you want to put on a pair of socks. You have 7 pairs of socks.

    You remember that you have forgotten to match the socks yesterday, so they are all loose. How many socks must you take out to ensure that there will always be at least one matching pair?

    QM
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    Depends whether they're all the same sock.

    If you have 7 black ones. 2. If you have 7 odd sock you're not going to get a pair. If you have at least one matching pair out of the 7 then 4.
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    Can they read the guards body language since he knows the result of the other persons coin toss?
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    (Original post by Quiz Master)
    Yes, if either of them guess correctly, they both live.

    QM
    You said A and B have no way to communicate. I'd count "shouting" as being able to talk.
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    (Original post by Quiz Master)
    Question 2: you are in the dark, and you want to put on a pair of socks. You have 7 pairs of socks.

    You remember that you have forgotten to match the socks yesterday, so they are all loose. How many socks must you take out to ensure that there will always be at least one pair?

    QM
    Two socks, you haven't specified that the socks you want to wear must match
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    (Original post by That Bearded Man)
    You said A and B have no way to communicate. I'd count "shouting" as being able to talk.
    They agreed beforehand which one would say the same as their coin toss and which one would say different. After that there was no communication

    QM
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    (Original post by 04MR17)
    Depends whether they're all the same sock.

    If you have 7 black ones. 2. If you have 7 odd sock you're not going to get a pair. If you have at least one matching pair out of the 7 then 4.
    7 different pairs = 14 socks, 7 different types

    QM
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    (Original post by Quiz Master)
    They agreed beforehand which one would say the same as their coin toss and which one would say different. After that there was no communication

    QM
    Ah got you.

    Genius. Very good.
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    (Original post by Quiz Master)
    7 different pairs = 14 socks, 7 different types
    Assuming you want a matching pair, 4. Or as That Bearded Man says, if you don't then 2.
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    (Original post by 04MR17)
    Assuming you want a matching pair, 4. Or as That Bearded Man says, if you don't then 2.
    Not 4

    QM
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    (Original post by Quiz Master)
    Not 4
    Well it depends on the question as I've said.

    I've said 2 given a particular interpretation. Since you've not said that's wrong twice now then I'm assuming it is 2.

    If not then I don't know.
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    (Original post by 04MR17)
    Well it depends on the question as I've said.

    I've said 2 given a particular interpretation. Since you've not said that's wrong twice now then I'm assuming it is 2.

    If not then I don't know.
    It is not 2 either

    QM
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    (Original post by Quiz Master)
    It is not 2 either
    Then I don't know.
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    (Original post by Quiz Master)
    The strategy was one of them would say the result of their coin toss (so if the toss was heads, they would predict the other coin toss was the same), while the other person would predict that the coin toss was different.

    This way they are guaranteed to survive an extra day

    QM
    But you said they couldn't communicate to each other so there is no way the second person would know what the first call was.
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    (Original post by Guru Jason)
    But you said they couldn't communicate to each other so there is no way the second person would know what the first call was.
    The first one knows the first coin and guessed the second coin is the same

    The second one knows the second coin and guesses the first coin is different

    QM
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    (Original post by Quiz Master)
    The first one knows the first coin and guessed the second coin is the same

    The second one knows the second coin and guesses the first coin is different

    QM
    But they guess each others, not their own. If I flip and get heads. I can guess the other is heads but it's only still 50/50. You either missed a part in the op or it doesn't work out.
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    (Original post by Guru Jason)
    But they guess each others, not their own. If I flip and get heads. I can guess the other is heads but it's only still 50/50. You either missed a part in the op or it doesn't work out.
    The two coins can either be

    HH
    HT
    TH
    TT

    If it’s HH or TT then the person who guessed the other coin is the same as theirs was correct.

    If it’s HT or TH then the person who guessed the other coin was different to theirs is correct.

    Since one of them guesses the same (HH and TT) and the other one guesses different (TH and HT)

    Therefore one of them will be correct.

    QM
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    (Original post by Quiz Master)
    The two coins can either be

    HH
    HT
    TH
    TT

    If it’s HH or TT then the person who guessed the other coin is the same as theirs was correct.

    If it’s HT or TH then the person who guessed the other coin was different to theirs is correct.

    Since one of them guesses the same (HH and TT) and the other one guesses different (TH and HT)

    Therefore one of them will be correct.

    QM
    But that wasnt the question you asked.

    I saw it a A guesses B coin as either H or T. And B guesses A coin as H or T. Both is 50/50 unless they know the outcome of the other why they can't as no communication.
 
 
 
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