Einstein's Conundrum

[Fish and Chips]

This is a riddle allegedly written by Albert Einstein himself. According to popular legend surrounding its creation, only 2% of the world population should be able to solve it. I just worked it out myself after messing around for about 40 minutes. The solution is completely logic based, and a good mental work out.

SPOILER TAG YOUR ANSWER. [ spoiler ] [ /spoiler ]

And include your personal timing if you kept it.[spoiler]Like this. 40 minutes.[/spoiler]Five men of five different nationalities live in five different houses, each painted a particular color. Each man enjoys a distinct type of beverage and smoke equally distinct cigar brands. They also all keep entirely different pets.

Who keeps fish?

1. The Brit lives in a red house.
2. The Swede keeps dogs as pets.
3. The Dane drinks tea.
4. The Green house is 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 man who smokes Blends has a neighbor who drinks water.

Hint: Making a table is useful.

Have at it. I'll quote the first person to reach the correct answer, though you can always compete for faster times.

If you are already familiar with this riddle, here's another tip - don't be a wiseguy.

[ClosetOtaku]

[spoiler]Unfortunately, I did not time myself when I solved this logic problem a while ago. I do remember trying it the first time in a traditional "grid" logic problem solution and found it was too difficult given the number of degrees of freedom. I switched over to a more elementary method - drawing the neighborhood - and was able to find the answer fairly quickly. The only real issue I had with the structure was what was meant "to the left of"... but in solving the problem, I noted that, in the end, the issue isn't relevant.[/spoiler]

[Bobtheduck]

While I haven't solved it, I think a question is in order:

[spoiler]Is it explicitly stated that at least one of the men does, indeed, own fish, and that the fifth man doesn't own something else? Fish aren't mentioned again after the initial question.[/spoiler]

[goldenspines]

My answer:

[spoiler] My time, 31 minutes, but I'm probably wrong. XD
My process was very confusing, but I basically started at the Norwegian's house and worked my way from there. I worked as quickly as I could, so I may have left out a missing piece (or more), but if not, the German keeps fish.

The Norwegian keeps cats, drinks water, smokes Dunhill, and lives in the yellow house.
The Dane keeps horses, drinks tea, smokes Blends, and lives in the blue house.
The Brit keeps birds, drinks milk, smokes Pall Mall, and lives in the red house.
The German keeps fish, drinks coffee, smokes Prince, and lives in the green house.
And the Swede keeps dogs, drinks beer, smokes Blue Master, and lives in the white house.
*gasps for breath* [/spoiler]

[Fish and Chips]

While I haven't solved it, I think a question is in order:

[spoiler]Is it explicitly stated that at least one of the men does, indeed, own fish, and that the fifth man doesn't own something else? Fish aren't mentioned again after the initial question.[/spoiler]

Being a trick question would sort of defeat the purpose of it being a logic problem.

EDIT: Mary is correct, including all the details.

[Kung_Fu_Master]

[spoiler]I don't think I got everything right but it was the German with the fish, right? I got 33 minutes but I'm betting there are a few things wrong.[/spoiler]

[Nate]

I almost want to do this but I think watching Kamen Rider Black is probably a better use of my time. Also man if Einstein wrote it I won't even come close to solving it, the best I could hope for is a wild guess and I can do that without spending half an hour. XD See watch.
[SPOILER]It's totally the Swedish dude because I see Swedish Fish in the candy aisle all the time so obviously he would have the fish, I mean who ever heard of British Fish or German Fish?[/SPOILER]

[minakichan]

[SPOILER]22 minutes, table, German. I'd done this before, so I know I could have done faster if I had used a predrawn table that wasn't so messy.[/SPOILER]

Incidentally, I think this problem isn't accurate, so I'm going to change it up a bit:

1) British people like fish and chips; they don't eat pets though, like uncivilized people would.
2) A Great Dane is a kind of dog, so obviously the Dane has the dog.
3) The man who smokes Blue Master has a blue house. Duh.
4) A Danish is a breakfast food. The strongest drinks associated with breakfast are milk and coffee, so the Dane drinks one of these. (Tea really should be associated with the afternoon.)
5) Incidentally, of course the Brit loves his afternoon tea. And scrumpets.
6) Isn't Norway, like, really cold or something? And it snows a lot? It's November now; what color do you THINK it'd be?
7) Germans drink beer of course. What kind of German wouldn't?
8) A fish lives in a house with a lot of water. Of course, water can be used to steep tea or make coffee.
9) No animal lives next to another animal that it would chase or eat.
10) Prince is smoked by a man whose home country has one.
11) What Nate said.

[SPOILER]OK, it doesn't work and I don't know anything about cigars. Someday I'll sit down and actually work something like this out...[/SPOILER]

[Ingemar]

I think part of this logic game requires you to make an assumption at one point, fill in the gaps based on your assumption, and check your work based on the premises. Which brings us to tip number 2:

"Use a pencil."

[Fish and Chips]

I almost want to do this but I think watching Kamen Rider Black is probably a better use of my time.

Nate raises a valid point.

It is excusable to postpone this and all other riddles if you are instead watching Kamen Rider Black.

The rest of you, however...

[Dante]

Drats, almost had it last night but accidently made a mix up between Swede and Norwegian that caused me to throw all of my work out. I'll tackle this with more time... simply because it is fun. Not difficult, just long. I wouldn't say smart as much as any person who has had a course in logic or mathematical proofs (e.g. understands how to use a proof by contrapositive argument or proof by contradiction, cases and while not used here proof by complete induction ect.). Some understanding of set theory would help as well.

Beyond that, it's just a long drawn out segment of weird looking mathematics most people aren't used to playing with.

[GeneD]

I got the same as Goldy, except I swapped the last two houses (if she gave hers in order). I've done the puzzle before, but a long time ago. I did it in 23 minutes, but there was a point that you have to make a guess and I got lucky there.

[goldenspines]

I got the same as Goldy, except I swapped the last two houses (if she gave hers in order). I've done the puzzle before, but a long time ago. I did it in 23 minutes, but there was a point that you have to make a guess and I got lucky there.

Actually, about the guess, I thought I had to make one too (about the Brit or Swede or something), but there was evidence for it there, just hard to spot at first. >.o

[Etoh*the*Greato]

I clearly don't belong in the 2%. I ran the puzzle for about ten minutes and couldn't figure out how to fill the gaps. I stand, ashamed, before my comrades.

[Fish and Chips]

I find it sort of interesting that a few of you said you (nearly) used some guesswork. Due to the form of the problem, it's actually possible to show your work, so guessing should be unnecessary; though if you were to take a stab at a guess, I think I can figure out where. One particular step is very difficult to see, and it's the last step before logically the table fills itself out due to the lay out of the clues.

[Fantasy Dreamer]

[spoiler]
The Norwegian keeps cats, drinks water, smokes Dunhill, and lives in the yellow house.
The Dane keeps horses, drinks tea, smokes Blends, and lives in the blue house.
The Brit keeps birds, drinks milk, smokes Pall Mall, and lives in the red house.
The German keeps fish, drinks coffee, smokes Prince, and lives in the green house.
And the Swede keeps dogs, drinks beer, smokes Blue Master, and lives in the white house.
*gasps for breath* [/spoiler]

Yes! I figured it out! I checked to make sure I was right on one before I was finished figuring out the rest of them though, so I had 'help'... but it took me...27 minutes... Mary is smarter than me! XD

[Kaligraphic]

Actually, Excel is very convenient for these sort of puzzles, as long as you give yourself the freedom to use more than five columns. Create arrangements using color to mark what goes with what, and you can easily move things around to see visually the logical arrangement of options. It ought to cut a bit of time off your run. (You could probably solve it in 10-15 minutes or so in Excel even if you aren't practiced in these puzzles.)

It also allows you to see the answer to the "guesswork" step more clearly. (If it's the step I'm thinking of, it's only hard/time-consuming because you have to fit a couple things in at once. It's much easier to identify the constraints on the board and fit it together in the scratch space.)

*edit* I missed the reference to guessing between the Brit and the Swede, so it may not be the same - I placed the Brit relatively early, but used that method for the German, Swede, and Dane. Still, the statement stands in principle, even if you do it in a different order than I did. */edit*

Oh, and for Bobtheduck - fish aren't stated again because the point is to solve the puzzle and figure out where they must be. Letting you figure out the final answer based on a partially-completed puzzle, then, would be counterproductive.

[Warrior4Christ]

Ah, I remember this from many years ago... I'll see how I do solving it again though.

[Doubleshadow]

I would have been faster but I found one of the clues was vague. XD I got it right after changing my assumption in about 9 min.