Zebra Puzzle - Text of The Original Puzzle

Text of The Original Puzzle

1. There are five houses.
2. The Englishman lives in the red house.
3. The Spaniard owns the dog.
4. Coffee is drunk in the green house.
5. The Ukrainian drinks tea.
6. The green house is immediately to the right of the ivory house.
7. The Old Gold smoker owns snails.
8. Kools are smoked in the yellow house.
9. Milk is drunk in the middle house.
10. The Norwegian lives in the first house.
11. The man who smokes Chesterfields lives in the house next to the man with the fox.
12. Kools are smoked in the house next to the house where the horse is kept.
13. The Lucky Strike smoker drinks orange juice.
14. The Japanese smokes Parliaments.
15. The Norwegian lives next to the blue house.

Now, who drinks water? Who owns the zebra? In the interest of clarity, it must be added that each of the five houses is painted a different color, and their inhabitants are of different national extractions, own different pets, drink different beverages and smoke different brands of American cigarets . One other thing: in statement 6, right means your right.

— Life International, December 17, 1962

The premises leave out some details, notably that the houses are in a row.

Since neither water nor a zebra is mentioned in the clues, there exists a reductive solution to the puzzle, namely that no one owns a zebra or drinks water. If, however, the questions are read as "Given that one resident drinks water, which is it?" and "Given that one resident owns a zebra, which is it?" then the puzzle becomes a non-trivial challenge to inferential logic. (A frequent variant of the puzzle asks "Who owns the fish?")

It is possible not only to deduce the answers to the two questions but to figure out who lives where, in what color house, keeping what pet, drinking what drink, and smoking what brand of cigarettes.

Rule 12 leads to a contradiction. It should have read "Kools are smoked in a house next to the house where the horse is kept", as opposed to the house, since the implies that there is only one house next to the house with the horse, which implies that the house with the horse is either the leftmost or the rightmost house. The text above has been kept as it is, as it is meant to be a presentation of the text of the puzzle as originally published.