Einstein's puzzle


Licensed User
It dated back at early '900 and it's said to be solvable by about 2% of the global population.
In the early 90s I wrote a Prolog program to solve this kind of problems when researching about the Natural Language Processing area of AI. It succeded 95% of times (the rest being infinite loops or out of memory cases).

The puzzle
In a street there are 5 houses, each characterized by a color. In each house lives a man of a different nationality. Each man drinks a different beverage, smokes a different cigarette brand and lives with a different animal. The question, given the below facts, is: can you say in which house lives the little fish?

1. The Englishman lives in a red house

2. The Swedish has a dog

3. The Dane drinks tea

4. The green house is on the left of the white one

5. The man in the green house drinks coffee

6. The man who smokes Pall Mall has small birds

7. The man in the yellow house smokes Dunhill's cigarettes

8. The man who lives in the middle house drinks milk

9. The Norwegian lives in the first house

10. The man who smokes Blends lives near the one who has cats

11. The man who has horses lives near the man who smokes Dunhill's

12. The man who smokes Blue Master drinks beer

13. The German smokes Prince

14. The Norwegian lives near the blue house

15. The man who smokes Blends has a neighbour who drinks water

Since I'm sure that everyone in our Forum will be able to solve the puzzle, please be honest if you decide to tell us the time it took for you.



Licensed User
I used 15sec to find the solution on Google to this page. :D

The fish is in the green house
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Licensed User
I guess that allowing Google's searches will take the 2% of population to almost 100% :)
If I recall it correctly my Prolog program took longer than 15s eheh


Active Member
Licensed User
One of my favorite classes in high school was Logical Thinking. We did a lot of these types of puzzles.