Who Owns the Zebra?

The solution can be summarized in the following table:

Solution to Who Owns the Zebra?
House #1 House #2 House #3 House #4 House #5
Norwegian Ukrainian Englishman Spaniard Japanese
Yellow Blue Red Ivory Green
Fox Horse Snails Dog Zebra
Kools Chesterfields Old Gold Lucky Strikes Parliament
Water Tea Milk Orange Juice Coffee

To get the solution, I filled in all the obvious data. This still left me with lots of clues that I couldn't easily analyze. However, my table of results had a simple choice: Japanese or Ukrainian in house number 2. Putting the Japanese there quickly led to problems; with the Ukrainian there I was able to proceed. I reached another impasse, and had to choose between having the green house in position 4 or 5. Again, after some thought, position 4 was impossible, and with the green house in position 5, the solution is quickly reached.

The zebra puzzle has become a useful example for certain kinds of constraint satisfaction problems. See, for instance:

Back to Who Owns the Zebra.

Last revised on 23 May 2008.