- In a street there are five houses, painted
five different colors.

- In each house lives a person of different
nationality.

- These five homeowners each drink a different
kind of beverage, smoke different brand of cigar and keep a different
pet.

Einstein's riddle is: Who owns the fish?

Necessary clues:

1. The British man lives in a red house.


2. The Swedish man keeps dogs as pets.

3. The Danish man drinks tea.

4. The Green house is next to, and on the left of the White house.


5. The owner of the Green house drinks coffee.

6. The person who smokes Pall Mall rears birds.

7. The owner of the Yellow house smokes Dunhill.

8. The man living in the center house drinks milk.

9. The Norwegian lives in the first house.

10. The man who smokes Blends lives next to the one who keeps
cats.

11. The man who keeps horses lives next to the man who smokes
Dunhill.

12. The man who smokes Blue Master drinks beer.

13. The German smokes Prince.

14. The Norwegian lives next to the blue house.

15. The Blends smoker lives next to the one who drinks water.

The complete solution is as follows:

Here is an explanation of the solution:

HOUSES: The Norwegian lives in the leftmost house, next to blue house.
The owner of the center house drinks milk, therefore, is not a green
house (whose owner drinks coffee). The green house is #4 since it is
to the left of the white house and there is no other place for a pair
of houses to fit. Therefore, the center house must be red and,
therefore, the Brit's house. The Norwegian's house is, therefore, yellow.
The Dane drinks tea and doesn't live in the coffee-drinking green
house. The Swede keeps dogs so he is not the person who owns horses
and lives in the blue house.

DRINKS: The man in the center house, the Brit, drinks milk. The green
house's owner drinks coffee. The Dane drinks tea so the Dane does not
live in the green house. The one who smokes Bluemasters drinks beer.
And since the German smokes Prince we know that the German does not
drink beer. The Brit drinks milk and so does not smoke Bluemasters.
Since the Norwegian smokes Dunhills, he can't do the Bluemasters/Beer
duo. And the Dane drinks tea, so the Swede must drink the beer.

SMOKES: The owner of the yellow house, the Norwegian, smokes Dunhill.
The German smokes Prince. The man who smokes Blends has a neighbor who
drinks water, and the green house #4 drinks coffee. Therefore, the
person in the white house #5 doesn't smoke Blends. The Dane does not
smoke Bluemasters since he drinks tea and not beer. The Brit does not
smoke Bluemasters since he drinks milk. The Norwegian doesn't smoke
Bluemasters since he smokes Dunhills. And the German smokes Prince,
not Bluemasters. So that means the Swede must smoke Bluemasters.
Therefore, the Swede also drinks beer.

PETS: The man who keeps a horse lives next door to the Dunhill smoker,
the Norwegian, so the owner of the blue house owns a horse. Since the
Norwegian smokes Dunhills, they do not have birds. The Swede keeps
dogs, so he is not the man who owns horses and lives in the blue
house. Whomever smokes the Bluemasters doesn't own birds.

When we find out the Swede smokes the Bluemasters and drinks beer, and
also know he keeps dogs, we know everything about him except which
house he lives in. He doesn't live in the red house because he drinks
beer not milk. He doesn't live in the green house because he drinks
beer not coffee. He is not in the yellow house smoking Dunhills and
since he doesn't own a horse, he isn't in the blue house. Therefore,
the Swede is in the white house.

The blue house and the green house are still unclaimed. The Dane must
be in the Blue house drinking tea, because he doesn't drink coffee, therefore, can't be in the green house. We already know that the Brit
is in the red house and the Norwegian is in the yellow house. So
finally, we can put the German into the green house.

So now we have the German smoking Princes and drinking coffee in the
green house. The Swede is in the white house smoking Bluemasters and
drinking beer with his dogs. The Norwegian is in the yellow house
smoking Dunhills. The Dane is in the blue house drinking tea and
owning a horse. Since he has a horse, he can't have birds and,
therefore, doesn't smoke Pall Malls, but rather Blends. The Brit is in
the red house drinking milk.

Since the Dane in the blue house smokes Blends, his neighbor must
drink water. The house next door, the Brit, already drinks milk, so
the Norwegian on the other side must be the one who drinks water. We
know what everyone smokes except the Brit, who by default smokes Pall
Malls, and then also owns birds. Since he owns the birds, the neighbor
of the Blends smoker who owns cats is the Norwegian, leaving only one
solution: The German owns the fish.