Whose Fish? (logic puzzle)

Yesterday I stumbled across this logic puzzle.

What always drives me crazy about stuff like this is that no one ever discusses the answer. I’ve never liked the implied wink wink smarty-pants attitude (see here). I want to know how someone arrives at the answer. What fascinates me is thinking, not trivia or secrets.

Here’s how I found the answer.

I don’t recall ever seeing this puzzle before and did not google it until I’d proven the results to myself. The puzzle is difficult, but I’ve posted answer at the end of the post, so you’ve been warned. The three little dots (∴) is the “therefore” symbol.

First I set up a 6×5 matrix of attributes then started highlighting and crossing out relevant details.

Then I got stuck.

Intuitively, I knew it all came down the Norwegian. This because we know he has only one neighbor. Everyone else can have one or two neighbors. Eventually, it came down to coffee (consumed and in clue 5).

The Puzzle:

There are five houses in a row in different colors. In each house lives a person with a different nationality. The five owners drink a different drink, smoke a different brand of cigar and keep a different pet, one of which is a Walleye Pike.

Who owns the fish?

The 15 clues:

  1. The Brit lives in the red house.
  2. The Swede keeps dogs as pets and gets their products from all the time.
  3. The Dane drinks tea.
  4. The green house is on the left of the white house.
  5. The green house owner drinks coffee.
  6. The person who smokes Pall Malls keeps birds.
  7. The owner of the yellow house smokes Dunhills.
  8. The man living in the house right in the center drinks milk.
  9. The man who smokes Blends lives next to the one who keeps cats.
  10. The Norwegian lives in the first house.
  11. The man who keeps horses lives next to the one who smokes Dunhills.
  12. The owner who smokes Bluemasters drinks beer.
  13. The German smokes Princes.
  14. The Norwegian lives next to the blue house.
  15. The man who smokes Blends has a neighbor who drinks water.

The end of this puzzle will have five units, each with 6 attributes: {address, house color, nationality, drink, pet and smokes}

The data seems to break down into two types: Definitive data, that which defines an attribute directly within one unit. And relational data, which defines an attribute relative to another unit. Relational data often acts as a negating definition as well, showing what isn’t in a unit by describing what’s nearby.

Now stepping through the clues, definitive data related to nationality first:

1. The Brit lives in the red house.
Brit == red
2. The Swede keeps dogs as pets.
Swede == dogs
3. The Dane drinks tea.
Dane == tea
10. The Norwegian lives in the first house.
Norwegian == 1st house
13. The German smokes Princes.
German == Princes

Next comes the secondary definitions. These can be used to reveal data which eliminates possible units based on what is already known:

5. The green house owner drinks coffee.
Coffee == Green ∴
Brit != coffee
Dane != Green
6. The person who smokes Pall Malls keeps birds.
Pall Malls == birds ∴
German != birds
Swede != Pall Malls
7. The owner of the yellow house smokes Dunhills.
Yellow == Dunhills ∴
German != Yellow
Brit != dunhills
8. The man living in the house right in the center drinks milk.
Milk == 3rd House ∴
Norwegian != milk
Dane != 3rd House
12. The owner who smokes Bluemasters drinks beer.
Bluemasters = beer ∴
German != beer
Dane != Bluemasters
First Second Third Fourth Fifth
Blue Green Red White Yellow
Brit Dane German Norwegian Swede
Beer Coffee Milk Tea Water
Birds Cats Dogs Fish Horses
Blends Bluemasters Dunhills Pall Malls Princes
First Second Third Fourth Fifth
Blue Green Red White Yellow
Brit Dane German Norwegian Swede
Beer Coffee Milk Tea Water
Birds Cats Dogs Fish Horses
Blends Bluemasters Dunhills Pall Malls Princes
First Second Third Fourth Fifth
Blue Green Red White Yellow
Brit Dane German Norwegian Swede
Beer Coffee Milk Tea Water
Birds Cats Dogs Fish Horses
Blends Bluemasters Dunhills Pall Malls Princes
First Second Third Fourth Fifth
Blue Green Red White Yellow
Brit Dane German Norwegian Swede
Beer Coffee Milk Tea Water
Birds Cats Dogs Fish Horses
Blends Bluemasters Dunhills Pall Malls Princes
First Second Third Fourth Fifth
Blue Green Red White Yellow
Brit Dane German Norwegian Swede
Beer Coffee Milk Tea Water
Birds Cats Dogs Fish Horses
Blends Bluemasters Dunhills Pall Malls Princes

Many of the relational data clues reveal additional information about what a unit doesn’t have:

4. The green house is on the left of the white house.
Green = White’s address – 1
9. The man who smokes Blends lives next to the one who keeps cats.
Blends = Cat’s address ± 1 ∴
Blends != cats
11. The man who keeps horses lives next to the one who smokes Dunhills.
Horses = Dunhills’ address ± 1 ∴
Dunhills != horses
Horses != Yellow
14. The Norwegian lives next to the blue house.
Blue = 2nd house ∴
Brit != 2nd house
Norwegian != Blue
15. The man who smokes Blends has a neighbor who drinks water.
Blends = Water’s address ± 1 ∴
Blends != water

The fourteenth clue is one of the most important. Since we know the Norwegian lives in the 1st house (clue 10), we know that the blue house is number 2. Number 4 is a tricky one, there is no reason to believe that the green house is the first house, all we know is that the white house is on it’s left. Also, clues 9 and 15 could be referring to one or two neighbors.

It’s interesting that the clues sort out into three quintuplets.

Here’s where it starts to get really hard. All that is known for certain is what was defined in questions 1-3, 10 and 13. There remain three or four unknowns for each unit. What I’m looking for is the first link in a causality chain. Of course it’s probably not so much a chain as a loop, so looking for an end is futile. How about an onramp?

After several minutes of staring, and re-reading the clues, I got the chills (really!)


The green house drinks coffee. The center house drinks milk. So the center house is not green. But the Green house is on the left of the white house. Since we know the second house is blue, we then know that the first house is not green either. So the only place the green house can be is fourth, making the 5th white. Now is the first yellow, or is the first red?

The elimination steps above provide the answer. We know the Norwegian is in the first house, and the Brit is in the Red house. That means the Brit is in the red house in the middle, drinking milk, and the Norwegian’s house is yellow and he smokes Dunhills.

Whoa, more chills.

At this point, the whole things starts to fall together.

Clue 11 puts horses in the blue house.
Clue 3 means the Dane is not in the green house
Clue 15 puts Blends in the second house, and, with clue 9, water and cats in the first house.
etc. etc.

The Answer

Here’s the final breakdown:

First Second Third Fourth Fifth
Yellow Blue Red Green White
Norwegian Dane Brit German Swede
Water Tea Milk Coffee Beer
Cats Horses Birds FISH Dogs
Dunhills Blends Pall Malls Princes Bluemasters

The German has the fish and drinks coffee in the green house, which is fourth on the block.

That was fun.

I hate puzzles.

Update: Here’s a programmatic solution to “Einstein’s Riddle” and another walkthrough by James Yates.

129 Responses to “Whose Fish? (logic puzzle)” Comments Feed for Whose Fish? (logic puzzle)

  • I don’t think it’s particularly fair to go posting the answers to this puzzle. is running a competition for this puzzle, with some pretty good prizes on offer, and you’ve just made it a whole lot easier for idiots to cheat. Some people will have spent a long time working on the answer, and you’ve just negated all those people’s efforts. Very considerate of you.

  • Hi! Im very impressed with how you got the answer. However, I figured it out within seconds after reading the riddle. I knew it was the German because Einstein was German. I tell jokes about Polish people because I myself am Polish! lol I will now leave you with a quote from Albert as a response to the other comment: “The secret to creativity is knowing how to hide your sources. “

  • Dear anonanonanon,

    This is not a new puzzle and the answers to this are all over Google.

    As for this posting, the answer is at the very end, there is a warning about it at the beginning and someone would have to scroll about four full screens to get to the paragraph where I start to put it together. Out of deference to your not entirely polite request, I’ve added a large warning header before that paragraph. Still, I doubt anyone looking for a quick answer would wade through my excessive canoodling.

  • Congratulations on your answer; I arrived at the same one.

    However, you define clue number 4 in a very convenient way. Just because the house in on the left, it does not have to be on the “immediate” left. So, the 1st house could be green and the 3rd house can be white. This makes House 4 yellow and House 5 red. After finishing the table this way, you come to the conclusion that the fish could belong to either the German or the Dane. Here is my 2nd table:

    House 1 | House 2| House 3 | House 4 | House 5 
    Green   | Blue   | White   | Yellow  | Red
    Norw.   | German | Swede   | Dane    | Brit
    Coffee  | Water  | Milk    | Tea     | Beer
    Pall M. | Prince | Blends  | Dunhill | Bluemas.
    Bird    | Cat    | Dog     | Fish    | Horse

    Notice also, the cat and fish can be interchanged. This is because Blends is inbetween the two. Also notice, that the green hosue in on the left of the white. In fact, all 15 clues work out perfectly in this example also.

    So this puzzle has two answers, or I am making a huge mistake somewhere.

    – Alex

    • you made a mistake. the green house is on the left side of the white, so it would be right next to it. right?

    • I noticed this when I solved it myself, but even if the green and white houses don’t have to be next to each other, I still ended at the conclusion that they were houses four and five.

  • Wow. Yeah, that does appear to work as well, at least i wasn’t able to disprove it easily. You’re right that the language of the fourth clue is sloppy and would literallly mean that the green house is anywhere from 1 to 4 houses left of the white house. I was fairly certain of my answer, but I think your interpretation of clue 4 is completely valid.

  • it could also be:

    House1   House2     House3   House4   House5
    German   Swade      Brit     Dane     Norwegian
    Green    White      Red      Blue     Yellow
    Prince   Bluemaster Pallmall Blends   Dunhil
    Coffee   Beer       Milk     Tea      Water
    FISH     Dog        Bird     horse    Cat
  • This answer also works:

    House 1| House 2  |House 3 |House 4 |House 5
    German | Swade    |Brit    | Dane   |Norwegian
    Green  | White    |Red     |Blue    |Yellow
    Prince |Bluemaster|Pallmall|Blends  |Dunhil
    Coffee |Beer      |Milk    |Tea     |Water
    FISH   |Dog       |Bird    |horse   |Cat 
  • And there was me thinking that the Dane was a dog kept by the swede, which was being grown in the green house with all the other vegetables. I feel silly now!

  • If we are going to get picky and it appears we are, clue # 15 is a little sloppy as well. Neighbor; One who lives near or next to another. Does not specifically mean next to as it is stated in clues # 9, 11, and 14. If one is to use this rational the whole puzzle becomes a mess. If you want to get into all the possibilities of the puzzle you have more time than I. I think that using the most “obvious” conclusions the answer is clearly the German, with coffee breath, smoking a prince, standing in front of the green house, wearing an “I love fish” shirt.

  • If you like these logic puzzles then you might want to try Sudoku puzzles that have become this year’s puzzle fad in UK newspapers. The times puts its ones online everyday (see here).

    The aim is to ensure that every box contains the numbers 1 though 9, and that every horizontal and vertical line contains 1 through 9. The puzzles rely on the same logical gymnastics as the fish puzzle, but without the narrative element. They come in varying difficulties – the easiest only needing basic logic and the hardest requiring you to work through mutliple contingent possibilities.


  • I also hate puzzles, but I did it just to prove to myself that I understand it conceptually and knew that it wasn’t so hard. And I succeeded. But puzzles are just work, as far as I’m concerned. :*)

  • Correction: “…understood…”

    p.s. Oh, not that I’m against work. As a graphic designer, I have to solve problems and puzzles all day long. And I don’t mind solving *those* puzzles. It just means I don’t like doing puzzles when I’m not in the office. :*)

  • What a great puzzle, if we get it are we in menze? I actually used Microsoft Excel to help with the graphing and coloring. The hardest challenge for myself was not getting the clues intertwined with each other. A true brain teaser and an enjoyable one.

  • Guess I’m a little late to the party- I’ve had the original puzzle bookmarked for like a month now until I actually had time to sit down and figure it out. I worked out the solution pretty much the same way as you did. One point to note though… It never specifes whether the Norwegian’s house (“the first house”) is the left-most or the right-most house. So if you are ordering them from first (Norwegian) to last, it could be either “Norwegian, Dane, Brit, German, Swede” or “Norwegian, Dane, Brit, Swede, German”. Given the way the puzzle is set up, it turns out that it doesn’t really matter what order the last two houses are in…

    I have to agree with the second poster, though. I suspected from the start that it was the German, but still had to go through the steps to prove it to myself. I was kinda surprised that he wasn’t a beer drinker, though.

  • we cheated. NARF NARF.
    twas good twsa good.
    sooooo. ich bin ein berliner. YABADABADOO!
    WERE ONLY YOUNG!! EWRE NOT THAT SMART! but we did alot, all by ourselves. twas good twas good. okay, byebye nowwww

  • In holland we like fish! why where there no dutchman in this puzzle!haha
    Now serious it was a really hard puzzle because ive just last night when out drink to much and to less sleep in the morning I saw that a friend of my posted this puzzle in my mailbox so..i went on it the same way as you did and in between 30 minutes a had the correct answer but thats because it is sooo logical peoplezzz! see ya

  • At guy who posted before me: Dude some of us check our answers with this joe maller…
    Thanks so much!

  • hi, i got given this puzzle at skool and thought i would have a go but come no where near close enough to solve it!!! it actually said down the bottom of the puzzle only 98% of people in the world have figured out the answer. and i think it’s great that u gave us the answer……hehehehe it doesn’t make me think, and i don’t like to think.

    • It said 98% COULD NOT get the correct answer. If 98% could, the puzzle wouldnt be so great now would it?

  • oh yeh, it’s me again, speaking of logic i thought that the person who drank milk was the cat!!! and that the cat and dog couldnt live next door to each other coz they fite anyway i now get the term “logic” lol

  • I used a slightly different approach but got the same answer (the German has the Fish). However, I have the houses ina different order. Goes like this
    Colors: Green-Blue-White-Yellow-Red
    Nationalities: Norw-Ger-Swede-Dane-Brit
    Pets: Birds-Fish-Dogs-Cats-Horses
    The main difference is that the Blends guy has a neighborm with cats and a neighbor with water. You have them as the SAME neighbor, which is not disallowed. I had them as different neighbors, one on one side, one on the other. Took me about 30 minutes.

  • My grade nine math teacher is makin us do this problem and it’s so hard

  • My boyfriend challenged me with this riddle that had been sitting on his desk for weeks… It only took two lunch breaks at work and a ton of scratch paper (since I apparently wasn’t brillant enough to utlize Excel), but I figured it out. Answer: The German has the fish and drinks coffee in the green house, which is fourth on the block.

    “Im a freakin’ genius!!!”

  • hi! thanks for posting the answer, i needed to make sure that i was right when i solved it. however, there’s something that is bugging me. You said, “But the Green house is on the left of the white house. Since we know the second house is blue, we then know that the first house is not green either.” Ok excuse my ignorance but why can’t the first house be green? I came to the two choices, whether to have the first house be yellow (the correct solution) and whether to have the first house be green (wrong) and i chose the first one. so please email me why if you have the time. thank you!

  • The beauty of this puzzle, and in math in general, is that “The first house” is never truely defined. We assume that the first house is on the left, more in part by the sociological aspect of syntax; We read from left to right, so, far left must be the beginning, ergo, house #1 is on the far left.

    In fact, all the symbols offered in this logic puzzle could be interchanged with any other symbols and we would still arrive at the same product! And yet it’s our generally accepted conventions- (green=the color green)(fish= a fish) that has us all arriveing at the same answer! How intresting!

  • I can’t believe I actually solved this. I’ve never been able to figure out a sudoku puzzle…this was so maddening. Once you get it organized on paper it does come together. So we are in the 2% , are we?? LOL

  • First of all, this is a great puzzle. Comes together well and considering it’s a logic puzzle, it only has one logical solution. The fact that everyone is splitting hairs goes against the fact that it is logical. Also, generally accepted conventions are different then logic, and given that the generally accepted convention of first being on the left could be changed, it doesn’t follow logic if it is. Symbols in this cannot be interchanged, they can be interpreted as they are intended by the maker of this LOGIC puzzle. If one is too look at this in detail, he/she will realize that the writer of this wrote it so that there is one logical solution, one solution that is correct, this one solution is the one that the writer based this problem off of, but when analyzed more in depth the creator made sure that as long as some sort of logic was followed, while it may not have been his/her own, the correct answer was still reachable. The fact that there is one answer that makes more logical sense is what im sure the statistic that “98% of people could not figure this out” is referring too. Sure, many people can figure out the answer, but only 2% of people reach it with perfect logic while others split hairs and cut corners in order to reach the answer.

  • Alex at 2:51pm on Sunday, August 7th, 2005,
    It can’t be that way, because it says that the Norwegian lives in the first house and near the blue house.
    I understand I am way tooooooo late, but I just saw this.

  • Yay! I feel super smart right now, as I managed to solve the puzzle.

    However, I wanted to know whether it really only is 2% of the population who can solve it. Personally, I felt it was just time and patience that was required; I’m sure everyone could derive the answer if you spent long enough on it!

  • The real answer to the question is, who said anything about a fish? There is no fact that indicates that the 5th pet is a fish, the answer to the puzzle is that you can’t truly answer who owns a fish. You can determine who owns the 5th pet, but is it a fish? How can you be sure?

    [a walleye pike is a fish. — joe]

  • dude your an idiot! We had three people in my house who figured out this puzzle seperately in about 20 to 30 minutes. Your explanation seems to just have a bunch of flowery language directed at talking over people. It’s simple, process of elimination & and a little mind muscle.

  • I did this problem at school and the answer to the riddle is…

    There is no answer.

    When Einstein said that only 2% of the population could answer this he ment it. If you look closer at each clue, not one of them says anything about a fish at all.
    The probability of a fish being in the German’s house is as likely as a zebra being in the house. The fish would have to be part of the clues in order to fit into a catagory. That’s why this riddle can be answered in less than 1 minute.

    [a walleye pike is still a fish. — joe]

  • The question clearly states “The five owners drink a different drink, smoke a different brand of cigar and keep a different pet, one of which is a Walleye Pike.”

    I don’t know about those who say the questions don’t mention a fish & blah blah. The questions states clearly that one of the pets is a fish, so that means the unmentioned pet is a walleye fish….

    Read the whole question people

  • Hey! it can be the german, or dane who smokes blend .. look at my solution.

  • Oh he meant DAnnish by “Dan” and british by “Brit” which messes up my solution..working on a new one

  • I finished this in 67 minutes, on one piece of paper, and I’m still in grade school…

  • mmmm… i started this and then realized that with the challenges at work (dont want to be caught do puzzles)the pressure to keep mentioned job the bills compressing the panic you could feel i came to this conclusion that over and above the fact that only a small % of people have access to computers in the world (yes starving Ethipians, war ridden countries etc)even less actually get emails regarding puzzles as they have strict emailing policies etc the 2% are people who to the rest of us 98% don’t even blink on the need to know you scale ask your self this and it’s a hard puzzle to figure out when last did you do something life changing for someone else!! privileged little geeks with less brains than sense! wake up your life is passing you by and you don’t even know it!! for the rest who had this as a project this lesson will teach you nothing valuable in Africa you use your hands and manual labour is daily privilege you interact with people and learn from thier lessons hope you will realize your purpose as to help others this helping yourself.

  • a thing to consider: einstein says the green house is on the left of the white, BUT not necessary on the immediate left, it could be couple houses down. therefore i got a different answer that is completely possible. the dane has the fish.

  • I graphed it out with five boxes representing the houses. Then I wrote inside the boxes each of the five facts as I logically derived them. Above each box I wrote what could *not* be in the box logically, with a little “X” next to it. Below each box I put in parentheses with a little question mark next to it, what *could likely* be in that box.

    Then I read through the clues over and over, refining the graph until all the variables were accounted for except the one missing pet entry. It took me about 2-3 hours.

    Steve S.

  • “In order to form an immaculate member of a flock of sheep one must, above all, be a sheep.” You are a sheep my friend.

  • OK that sounded good but after I read it like 5 times it no longer makes any sense.

  • OK again this has something to do with cloning and sheep love please delete my two above because I’m an idiot and wanted to say something cool.

  • @Mason. Yeah, I was thinking the same thing. I think I see what you were getting at, but I have no idea who or what you were referring to. But anyway, thanks for stopping by.

  • If Einstein said 2% it would probably mean 1% or less now. He probably though we wouldn’t make it this far. At least he got one thing wrong.

  • I solved this about a decade ago when i was in high school. It took me the entire night (minus homework and TV time, so about 4-5 hours), and several small squares of paper.
    Tonight, i tried to solve it again, and somehow managed to solve it in 15 minutes. My subconscious recalling the solution from 10 years ago? Nope…i just made an educated guess (cat and water both in the first house), and everything else fell into place on the first try.
    Sometimes it’s better to be lucky than good =)

  • Calvin, No, your answer is not valid.
    “The person who smokes Pall Malls keeps bird.”
    Not horses.

    Nice try though.

  • had to take a 40 minute break at work for this one. Fun.

  • I figure this out in my head last night when I should have been sleeping. Took about an hour.

  • Okay, I read through the first half and you guys kept referencing graphs and charts. I haven’t used those since I was in school and hated them. I figured this one out in about ninety seconds after stumbling upon the puzzle while looking for images for an art project.

    Please tell me I’m not the only freak who juggled this in his head?

  • The first time I received this puzzle I only had 14 clues. (no one told me the Norweigan lives in the first house) It took me two hours to conclude that there are 5 solutions. I googled it and found the missing clue. I started from scratch using elimination (all the variables written in excel tables) and it took me 5 minutes to find THE solution.

  • How long did it take you guys, took me about ten mins. It was fun, but to me I can’t see how no more than 2% of everyone in the world can actually get the answer. Maybe I’m thinking to highly of the intelligence of others.

    Wow that probably made me sound like a dick, oh well. ha

  • ok, so i completed this puzzle, and got a completely different answer than you, yet it still works with all of the clues.

    i got:

    1st: Norwegian, green, coffee, pasmall, bird
    2nd: German, blue, water, princes, cat
    3rd: Swede, white, milk, blends, dog
    4th: Brit, red, beer, bluesmaster, horse
    5th: Dane, yellow, tea, dunhill, FISH.

    is there a clue that i totally ignored or something?

  • Emma you ignored that the green house is on the immediate left of the white house.

  • Hi just figured i would let you know i also had a issue with this blog appearing blank also. Must be gremlins in the page.

  • hum
    that was tricky
    if you play soduko. use the same technique and it works.

  • Where in the 15 clues is anything said about a fish? Leaping to conclusions, I think!

  • I did it in 20minutes!!! Yeah man!!! Im a genius…

  • Well,, no assumption in this problem,, we can just start with a matrix 6X6 and the problem will be solved immediately,, starting with the facts like the milk and blue and the location is the important thing in this problem,, after that all things will run smoothly ;)

  • it took me 40 mins to solve this problem and i can say it’s not so difficult.this problem is easy to peaple that recently learning mathematics or someone who is frequently solve puzzles like sudoku

  • DON’T GIVE UP!!!!!!!

    I’m only 13 and I got the answer!!!!!

    Einstein’s kool :-p

    -Chels xoxox

    • I’m thirteen and I got it too! Nice work :)

  • Well, I agree with Mussab! I too used Matrix to solve this riddle n was quick in support with facts n clues.

    But infact, when someone brought me this riddle at first, I hit the answer right quick. It was pretty easy..
    Cuz the question was “Who owns the fish?”
    The answer is clearly “Fisherman” or u can say- “Aquarist”, as they are the most who owns the fish rather than People who keeps it in their room!
    After all this is a riddle as well…Haha!!

  • I got halfway through and couldn’t find the next link. Nice job walking through the answer, it was very helpful to see how you reached the solution.

  • A fish is not mentioned anywhere in the clues. Who owns the fish? There’s no mention of a fish…all you could LOGICALLY deduce from the problem who owns the four pets mentioned.
    That’s why only 2% solve the problem.

    This is the ONLY logical answer. You would only be ASSUMING that the German owns a fish.

    After taking the time to solve this riddle by process of elimination by making a detailed chart, it is ONLY possible to deduce that there is NO mention of what pet the German keeps. That’s the beauty of this riddle.

    If the process you used to solve this riddle actually gave the answer that the German owned a pet fish, well…than many more than 2% of people would be able to solve it because many people know this method of reasoning.

    At the first read-through I realized there was no mention of the fish in the puzzle ANYWHERE (find a copy of the original riddle if you doubt this).

    You CANNOT prove that the German had a pet fish; that’s Einstein’s genius and humor for you!

    • Duh!! The welleye pike?? Is what if not fish then… :)

  • By the way, the above answer is not a cop-out. I t IS the intended answer. I tis the only logical answer: There is NO way to prove who owned a fish.
    Again, you would be ASSUMING that since there is no mention of what pet the German owned (through your extensive deduction) that HE must own the fish. But since there is NO mention at all of a fish in the variables of the puzzle itself, you are merely filling in the blank with a “fish”. The joke’s on you (on all of us who have ever read this puzzle)!
    Again…this is TOTALLY Einstein all the way. The answer’s in the question, except this time it’s not! hahaha
    (I have the IQ to back up this answer. It’s so simple…that’s the sheer beauty of it!!!)

    • A Walleye Pike is a fish.

    • Your ASSUMING the reason 98% of people can’t solve it is due to IQ deficiency. Maybe the Intended answer was to make you think about the reality of the situation in the world population. 98% of people in the world are not educated to the level to perform basic algebra!
      Self serving Logic puzzle…or is it?

      • No algebra is needed.

      • *You’re
        From your tone, you seem to not count yourself among this ‘98%.’ I’m sorry, but, considering your grammatical ability, I am unable to take your words seriously. There are too many mistakes for me to be bothered to point out but I’ll try to ignore them for now and say this instead: you replied to the wrong comment, didn’t you?

    • I disagree that that is a true answer.  I see your point, but assumptions must be made in any situation.  Nearly any logic puzzle can be picked apart if you try hard enough.  Take the information “The man who smokes Blend has a neighbor who drinks water.” for example.  You could reason “perhaps this neighbor is across the street, and is therefore not part of the whole situation.”  This would entirely mess up the problem.  I don’t know if this was the intended answer, but a problem should not be thought of as a problem of “cheating the system” per se, but a problem of figuring out the puzzle with the information you are given.
      P.S. You mentioned your IQ to back it up.  I’ve always been curious about them and am really wondering what yours is.

    • luls…i agree with u. why cant we put fish in the blank. everyone have their own pet except german……Or maybe the answer is no one have the fish, i guess.

    • Wow you are an idiot. The fish is the walleye pike in the beginning. It was defined as a pet possibility.

    • A walleye pike is a fish. It’s just a process of elimination.

  • Guys, I must agree with much that you say and I have no doubt that you are all extremely smart – far smarter than me.  Yes, the puzzle is logicallly flawed since the Pike is not included as a variable within the ‘pet’ data type (which renders the puzzle insoluble) – but you appear to be looking at this incorrectly.  Yes, it is a data relationship puzzle but it is also a data hierarchical puzzle and until this is recognised it cannot be solved (or notionally solved, as is the case here).  It is only when you establish that that the house is at the top of the hierarchy that you can commence to solve it.  It is as well therefore to understand the principles of those that went before you and understand that hierarchy has an essential place in the relationships of data.

    Old Hand   

    • Only four pets are explicitly mentioned so the fifth had to be a fish. The reference to a wall-eyed pike was not in the original formulation. The problem is readily solved by logic and the clues can be reordered in such a way that it falls into place quite easily.

  • I used the same solution, but made it on a worksheet which I think made it easier, I started by organizing the ¨definitive data¨ (yellow) and then the ¨relative data¨ (orange), and then the remaining data filled the gaps. It took me about half an hour with this worksheet and it was very fun! 

  • great job! well done. puzzles need patience and hard work!

  • How did you come to the conclusion that the first house/Norwegian *must* have cats?  As far as I can tell, obviously the 2nd/blue/horse house is the Blends house, but the clues just say this house has a neighbor who keeps cats and a neighbor who drinks water.  It does not say that the same neighbor does both.  So, while the Brit/3rd house drinks milk, I can’t see why this house has the birds/Pall Malls instead of cats. 

  • it took me so long to get this because i didnt realize the cats and water could be in the same house. figured it out immediately after i realized that. twasnt that hard

  • I took the puzzle at face value and solved it using a matrix chart, instead of assuming things immediately. Also, my version (that I downloaded and printed) came with a chart that listed “fish” – so I was confused that others were confused about the fish issue. Aaaaand I thought it was silly and sneaky of you people to say things like “the green house might not be on the immediate left of the white house,” etc. I don’t know, who failed and who succeeded? 

  • Inferred that Green didn’t have to be immediately left to white, and that totally screwed me over :( 

  • it’s really hard to solve this puzzle there so many process…

  • Lol. I actually did this in 20 mins through trial and error. :D It was quite a challenge though!!!  And really thought I won’t be able to lol. Very cool. 

  • idot and logical

  • hes  a german  and fish

  • i used process of elimination and tactics i use for mastermind and Sudoku “if that goes there than that must go there” and i did it in half and hour yay =D

  • heh i remembered half way that albert e. was german and picked german, then looked for the awnser. And i was right.

    • Albert E didn’t identify as German at all. (Read his writings on that issue). He hated Germans and Germany. He thought them to militaristic and migrated to the US. If he was alive today – by some miracle – he’d leave the US for the same reason.

  • i just decided the german had the fish… i don’t know if i am just really lazy, or if i am a genius, because i just knew. the german had the fish…

  • one minute

  • i was really enjoyed in solving this problem …….but the end ,i didn’t end up in a right answer………so tricky you know..

  • Hey, I am 14. I did this riddle with my sister who is elder than me. We both collaborated and together we came up with the right answer. Working together and believing in yourself are the keys to success! Never Give UP, Believe That You Can DO IT And Trust ME YOU CAN DO IT! :)
    2:20 Am

  • Hey, I am 14. I did this riddle with my sister who is elder than me. We both collaborated and together we came up with the right answer. Working together and believing in yourself are the keys to success! Never Give UP, Believe That You Can DO IT And Trust ME YOU CAN DO IT! :)
    2:20 Am

  • I don’t know how, but I solved it by just staring at it… I did not use any kind of graph, pen or paper… matched the answer later and its correct… took me around 5 mins, which is quite a difficult job for an ADHD person to focus on something constantly for 5 mins … :)

  • Lol, I’m sure more than 2% can get this. It was really pretty easy. Got it in around 10-15 minutes. The whole “2% can solve it” thing was probably so that people would want to attempt it in the first place. Or to make people feel good about themselves.

  • I am 13 and I got this right!

    • nobody cares.

    • lol hun i am 11 and i got this right ._.

  • I did in 8 seconds and I’m only 3 months old.

    • Wow baby josh you are one smart child. Are you in college? That would be so funny if you were a baby in college

    • I did it in 0.1 seconds before I was born. First I changed the order of the clues and it fell into place in no time.

    • Really, I bet you can’t solve this one

  • This can be solved in 10-15 minutes by cutting out pieces of paper with all 25 of the attributes on them (5 house colors, 5 nationalities, 5 cigars, 5 drinks, 5 pets) and then taping together the pieces that have absolute relationships (Brit + red, Swede + dog, etc). Then moving on to the relative relationships, then using process of elimination to put the other slips of paper in likely places. You’ll wind up with five columns of slips of paper. Found this easier than trying to write down tables on a piece of paper since spatial relationships are also important.

  • I did a 5×5 grid with large boxes. The first row was nationality, then color, then drink, pet, smoke. For the first column, I wrote in “Nor” for Norwegian- and across the nationality row in all the other boxes I wrote, in small letters on the right margin in the box “-Nor”. I continued with this for Blue and Milk.

    For instances where there was a chance of a value in a field, I wrote in the value small with a “+” .

    After changing the clues to values like you did above, as you fill the grid following those clues, it’s very easy to see what possibilities you have.

    I am hoping to write a program to solve the riddle, although it’s looking like the task is far beyond my feeble programming skills.

  • The best way to solve this puzzle is by talking to yourself

  • I’m 11 and got this right

  • If you’re used to sudoku, it’s not too hard to figure out. The logic is similar.

  • Like Emma, I read clue #4 as saying the green house is somewhere to the left of the white house, not necessarily its immediate neighbor. (Like Joe and Emma, I assumed the houses are arrayed left to right, with the first house on the left.) And I got an answer that matches all the clues and is different from both Joe’s and Emma’s:

    1st: green, Norwegian, coffee, Pall Malls, birds
    2nd: blue, German, water, Princes, fish
    3rd: white, Swede, milk, Blends, dogs
    4th: yellow, Dane, tea, Dunhills, cats
    5th: red, Brit, beer, Bluemasters, horses

    So here’s the next level of this puzzle: How many different solutions (and what are they) that match all the clues if you put the green house somewhere to the left of the white house, but not necessarily next to it?

    I don’t have the answer–thought someone might have fun looking for it.

  • the german is Einstein

  • i’m 13 and got it in 30mins!

  • Lol me and my sister solved in 20 min. And we’re only like 11.

  • i do prefer to answer that the person who drink water owns the fish…
    1st Fish lives in the water.
    2nd, he ask WHO owns the fish?, not what house or what nationality owns the fish..
    AND i think that question make you crazy (LOL) !!!

  • i like it

  • Here’s my solution in 16 steps:

    1. Norwegian is first house, next house must be blue.

    2. White and green houses are next to each other so neither can be first house

    3. Red is British so also cannot be first house.

    4. Yellow is only remaining colour that can be first house, so Norwegian is Yellow house.

    5. Yellow smokes Dunhills and Dunhills is next to horses so Norwegian house is Yellow and Blue house owns horses.

    6. Green is left of white so is either 3rd or 4th house, however 3rd (centre) house drinks milk & Green drinks coffee so must be 4th house.

    7. Dane is either 2 or 5 (1 is Norwegian and 3 & 4 are Milk & Coffee).

    8. Bluemaster smoker is either 2 or 5 but cannot be Dane (drinks Beer not Tea)

    9. German must be 4 – cannot be 2 or 5 (Danish or Bluemaster smoker) or 1 or 3 (Norwegian or British).

    10. Swede keeps dogs so must be 5 (Norwegian, Horses, Brit and German are 1 to 4).

    11. Dane takes second (Blue) house as last remaining house.

    12. Blends smoker must be Dane (2nd House) as 2,3 and 4 don’t drink water and 4 smokes Princes.

    13. Last house (white) must be Bluemaster smoker as its last house without a drink (Beer).

    14. Middle house (Brit) must be Pall Mall smoker, all other houses accounted for.

    15. Norwegian house (1st house) must have cats as its next door to Blends smoker (the Dane).

    16. The German house (4th house, green) must have the Fish!

  • Its not mathematically solveable problem… But shere logic…. The einstien asked direct question.. The answer is you sir einstien the german or green house owner… But you might challenge this by saying their is nowhere he refer himself to be part of the puzzle or did mention he is supposebly owner of one of the houses…..

    But since he didnt mention this fact its us our duty to fill up the fact the way we deemed right….

  • The idea of the riddle is not the logic part of it, because after all it is not written that the riddle has to be solved with logic, although logic is used in order to solve the riddle. But that doesn’t mean that you have to think logically. and the part about the 98%? As you can understand by using LOGIC, only 2% WERE able to do it, meaning that this was the situation in his time, but today education is better, a lot more than 2% of the population can answer this problem, meaning that we HAVE become better. And the part about the 2%? Only 2 percent were able to except the fact that the German owns the fish, without questioning it too much.
    Did you know that Einstein was Jewish? You can look it up

  • How long did it take you to solve the puzzle? When I was 17, our school work was done for june and the teacher gave us this puzzle. I solved it in exactly ten minutes. I was an E (failing ) student at the time and I had two straight ‘A’ students sitting along side me who couldn’t solve it. the teacher siad I should go over the problem again, which i did in two or three more minutes and returned it to Him. It was correct! At that time in school, I also had an extrordinary aptitude for mechanical ability. My chart for it had a line going at least three inches above the top line on the page. But the teachers only gave me typing to do at that time.
    It’s a shame more girls don’t excel in life because of the sterotypical attitudes of the world. I am 68 today and have done no great thing in my life, even though I the logic of Einstein. What road would my life have taken, if I had only been recognized for my logic rather than my sex?

  • I already found this solution. But I also some more solutions in a different way to the same kind of puzzle in here

  • Technically the fish is mentioned in the problem. Its like any logic puzzle taught to elementary children quite simple and uses deductive reasoning skills. Einstein’s estimate of 2% has no basis in our society because we have advanced since his time. That percentage was based in his own time. Nowadays their are young children who could solve this puzzle in a few simple steps. During Einstein’s time many people didn’t graduate highschool or even enrolled.

  • This is indeed the correct answer. All the commenters who say you can never know for sure who owns the fish and all this nonsense are wrong and the only reason you say that is because your deductive powers are futile. i am a philosophy major taking special interest in logic and argumentation and am a semester away from pursuing a masters degree in this type of inferential logic.
    if you don’t understand what the question is asking of you, then you will never have the chance to comprehend the puzzle. I will take you on a philosophical history lesson for a second to prove that this must be the case. Take a look at the philosopher Pierce. All knowledge is a result of some inferential process. Therefore knowledge is fundamentally discursive. This question is asking you to look at the rules and conditions of the puzzle, but more importantly, it is asking what dp these rules imply. How does the combination of the rules affect the other places on the board. If you look pragmatically at every rule then you will not get very far. That is why Einstien said only 2% of the population would understand and be able to complete this puzzle. Premised on the fact that not everyone has the ability to enter into a strain of continuous inference. Some inferences you need to make ontop of inferences. It is literally a mental game of wits and connections. if one lacks the ability to abstract from the rules and decipher the implications of these rules on THE OTHER SPACES. Einstien thought radically different from everyone else, therefore he does not expect you to look at the rules themselves. But what these rules tell you about the situation in the next tier of reality if I can put it that way.

    Also I am indeed impressed with your line of logical reasoning. I am not sure if you wrote out your work on here in a purely methodological aim, but I did not perform that much written work to figure it out, but maybe thats because you wrote out the information to show the inferential process you are doing in your head. If so congrats you did extremely well. There is different key rules that you must infer as a conjunction to proceed in finding who has the fish.
    But what I really came on here to say is that anyone who thinks there is not an answer or that you can never know definitively, you are just being a linguistic pest who is playing around with words, with the malicious Cartesian intent of destroying all foundations of our knowledge. Something does not need to be clearly and distinctly stated in order for you to cognize it in an inferential process.

  • I see the conflict between 10th and 14th statement.

  • They are the fish

  • Green is on the left of White(not just after) it means it can be Blue Green Yellow white. And actually not German owns fish

  • I own the fish because I ate the fish!

  • When I did it, I got the Norwegian…

  • Took me approximately 35 minutes. I got the same answers. I was able to fill in 11 of the 25 spaces using logic, and then I randomly put that the white house contained the Swede and that the blue house contained the Dane (and as a result the green house contained the German) and went from there. Had I been shown that I mixed two or three of those up, I would have tried another combination, but fortunately, I got it right on my first try.

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