OK, probably not the fastest way of doing it, but for those who want a methodology the following is the steps I took to get to the answer. It helps to use a grid in excel or on a piece pf paper to keep track of the positive and negative statements, and after a few of the questions you can loop back to fill in blanks before going on to the next statement and so on, hence the multiple paths to the correct solution.
1) Brit lives in a red house
2) Swede keeps dogs
So dogs are not in a red house because the Brit lives there
3) Dane drinks Tea
So tea not drunk in the red house because Brit lives there
Dogs not associated with tea as the Swede keeps dogs and the Dane drinks Tea
4) Green house next to, and on the left of the white house
White house is not on the extreme left of the row, Green not on extreme right
5) Green house drinks coffee
Brit doesn’t drink coffee, he is in the red house
Dane doesn’t live in the green house, he drinks tea
Extreme right doesn’t drink coffee
6) B+H smoker rears birds
Swede doesn’t smoke B+H, he keeps dogs
7) Yellow House smokes Dunhill
Brit doesn’t smoke Dunhill, he lives in a red house
Dunhill smoker doesn’t drink coffee, coffee is drunk in the green house
B+H not in the yellow house, birds not reared in the yellow house
8) Centre house drinks milk
Dane not in Centre House, he drinks tea
Green house not in centre since green owner drinks coffee
White house not 4th from left as green is not in the middle
9) Norwegian lives in the first house
First house doesn’t drink Tea, nor own dogs
Norwegian doesn’t own the white house
First house is not red, the Brit lives in the red house
Norwegian doesn’t drink milk
10) JP smoker lives next to the one who keeps cats
JP smoker doesn’t keep cats
11) Horse keeper next to the man who smokes Dunhill
Horse keeper doesn’t smoke Dunhill
Horse keeper doesn’t live in the yellow house
12) Man who smokes Marlboro drinks beer
Dane doesn’t smoke Marlboro since he drinks Tea
Marlboro smoker doesn’t live in the green house
Beer drinker doesn’t live in the yellow house
Marlboro not smoked in the middle house
Marlboro not smoked by the milk drinker
13) The German smokes Embassy
Embassy smoker is not in the red house
Embassy smoker doesn’t keep dogs or birds
German doesn’t keep dogs or birds
Embassy smoker doesn’t drink tea
Embassy smoker doesn’t live in the first house
German doesn’t live in the yellow house or drink beer
14) Norwegian lives next to the blue house
Blue house must be 2nd in the row as Norwegian lives in the first
Blue house doesn’t drink milk
Brit doesn’t live in the second house
Dunhill not smoked in the second house
Green house is not the first house, so must be the 4th house
White house must be the 5th house, Red must be the third house, Yellow the first
Brit lives in the third house and must drink milk
Norwegian lives in the yellow house
Norwegian smokes Dunhill
Coffee is drunk in the 4th house
4th house is not lived in by the Dane
Horses kept in 2nd house
Swede doesn’t keep horses or live in the second house
15) JP smoker has a neighbour who drinks water
Eliminations and assertions after Q15 in the order I did them, note that there are multiple paths to the solution and this is only one of them:
Norwegian doesn’t keep birds or horses
Norwegian doesn’t drink coffee
Norwegian must drink water
Yellow house drinks water
German drinks coffee and lives in the green house
German lives in the 4th house, Swede the 5th house and Dane the second
Dane lives in the blue house with horses, Swede the white house with dogs
Dane cannot smoke B+H as he doesn’t rear birds
The Brit rears birds and smokes B+H, the Swede smokes Marlboro, Dane smokes JP
Embassy is smoked in the green house by the German
Cats kept next to the JP smoker, JP smoker therefore in houses 1,3 or 5
JP smoker is the Dane, Dane lives in blue house 2 so cats in 1 or 3.
House 3 has birds so cats kept in house 1 by the Norwegian
So…. Fish must be kept by the German!
Steve.