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Thread: hardest logic puzzle ever!!!!!

  1. #1 hardest logic puzzle ever!!!!! 
    Forum Freshman mathformonkeys's Avatar
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    1.Three gods A, B, and C are called, in some order, True, False, and Random. True always speaks truly, False always speaks falsely, but whether Random speaks truly or falsely is a completely random matter. Your task is to determine the identities of A, B, and C by asking three yes-no questions; each question must be put to exactly one god. The gods understand English, but will answer all questions in their own language, in which the words for yes and no are 'da' and 'ja', in some order. You do not know which word means which



    2 not that hard but still a logic puzzle


    There are five houses.
    The Englishman lives in the red house.
    The Spaniard owns the dog.
    Coffee is drunk in the green house.
    The Ukrainian drinks tea.
    The green house is immediately to the right of the ivory house.
    The Old Gold smoker owns snails.
    Kools are smoked in the yellow house.
    Milk is drunk in the middle house.
    The Norwegian lives in the first house.
    The man who smokes Chesterfields lives in the house next to the man with the fox.
    Kools are smoked in the house next to the house where the horse is kept.
    The Lucky Strike smoker drinks orange juice.
    The Japanese smokes Parliaments.
    The Norwegian lives next to the blue house.
    Now, who drinks water? Who owns the zebra?


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  3. #2 Re: hardest logic puzzle ever!!!!! 
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    Quote Originally Posted by mathformonkeys
    (01) The Englishman lives in the red house.
    (02) The Spaniard owns the dog.
    (03) Coffee is drunk in the green house.
    (04) The Ukrainian drinks tea.
    (05) The green house is immediately to the right of the ivory house.
    (06) The Old Gold smoker owns snails.
    (07) Kools are smoked in the yellow house.
    (08) Milk is drunk in the middle house.
    (09) The Norwegian lives in the first house.
    (10) The man who smokes Chesterfields lives in the house next to the man with the fox.
    (11) Kools are smoked in the house next to the house where the horse is kept.
    (12) The Lucky Strike smoker drinks orange juice.
    (13) The Japanese smokes Parliaments.
    (14) The Norwegian lives next to the blue house.
    The Norwegian lives in the first house (09). So his house isn’t blue (14). Since that’s the colour of the house next door, his house isn’t green or ivory either (05). Therefore the Norwegian lives in the yellow house.

    So the Norwegian lives in the first house, which is yellow, and smokes Kools (07). Therefore he doesn’t drink coffee (03), tea (04), milk (08) or orange juice (12). Hence …

    The Norwegian drinks water.


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  4. #3  
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    So the house next to the Kools-smoking Norwegian’s is blue (14), and the occupant owns the horse (11). We know that the Norwegian drinks water, so water is not consumed there. Neither are milk (08) and coffee (03). So the beverage of the second house is either orange juice or tea.

    I claim that it is tea. To prove this, assume to the contrary that it’s orange juice instead. Then the occupant smokes Lucky Strike (12) and so couldn’t be the Japanese (who smokes Parliaments (13)). Nor can he be the Englishman (who lives in a red house (01)), the Spaniard (who owns the dog (01)) or the Norwegian (who lives next door). So he must be the Ukrainian. But the Ukrainian drinks tea (04). This is a contradiction; hence the assumption that orange juice is drunk at the second house is invalid.

    So the tea is drunk in the second house, meaning the Ukrainian lives there (04). Therefore he does not smoke Kools (the Norwegian does), Lucky Strike (smoked by the orange-juice drinker (12)), Parliaments (smoked by the Japanese (13)) or Old Gold (smoked by the owner of the snails (06)). Hence he smokes Chesterfields.

    The rest is complicated by the fact that it is not mentioned whether the first house is the one on the extreme left or the one on the extreme right. But it doesn’t matter. In both cases, the Japanese owns the zebra.
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  5. #4  
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    If the first house is on the left we have this



    while if the first house is on the right, we have this:



    The Japanese doesn’t own the horse, dog (02) or (since he smokes Parliaments (13)) snails (06). So he owns either the fox or the zebra. Suppose, for the sake of contradiction, that he owns the fox. Then he must live next to the Chesterfields-smoker (10) – i.e. at #3. Since the green and ivory houses must be next to each other (05), the red house can’t be #4 – i.e. the Englishman doesn’t live at #4 (01). If the Japanese is living at #3, then the Englishman must live at #5. Therefore the red house is #5. Therefore (since coffee is drunk at the green house (03)) orange juice is drunk at #5 (by elimination) and so Lucky Strike is smoked at #5 (12) by the Englishman. Therefore (since the Japanese smokes Parliaments (13)) the Spaniard smokes Old Gold (by elimination). But the smoker of Old Gold owns snails (06) whereas the Spaniard owns the dog (02). Contradiction! So the supposition that the Japanese owns the fox is untenable. Hence, the Japanese owns the zebra.
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  6. #5  
    Administrator KALSTER's Avatar
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    I once did this puzzle in 20 minutes while drunk, but took 45 minutes 2 years later while sober!
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
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  7. #6  
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    It’s actually quite easy to solve this puzzle by trial and error – but I insist on being attentive to details.
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  8. #7  
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    I love this one, I actually solved it in an hour on a transaltlantic flight. Its great!
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