Solution to Einstein's Riddle

Solution to Riddle of the Week: Einstein's Riddle

Difficulty level: Hard

By Jay Bennett

Did you figure out who keeps fish? If not, start filling in this chart and see how far you can get. You can see the original question here.

SOLUTION

Start with the pieces of information given to you: the Norwegian lives in the first house (clue 9), and the man in the center house drinks milk (clue 8). Fill these in on the chart. These are just like the starting numbers in a Sudoku puzzle.

Now begins the long process of deduction. You know that the Norwegian lives next to the house with blue walls (clue 14), and there is only one house next to the first house, so house 2 has blue walls.

Now you need to look at clue 4 and 5 together: the owner of the house with green walls drinks coffee (clue 5), and the house with green walls is just to the left of the house with white walls (clue 4). The green walled house with the coffee drinker cannot be house 2, because that house has blue walls, and it cannot me the middle house (house 3) because the owner of that house drinks milk. So it the house with green walls and the coffee drinker is house 1, 4, or 5—but it also needs to be directly to the left of the house with white walls, which eliminates house 1 and 5 because the white walled house cannot sit to the right of house 1 or 5. So now you now that house 4 has green walls and the coffee drinker, and you know that house 5 has white walls.

And so on and so on, until you find the fish. Perhaps the trickiest deduction you have to make along the way is finding out who drinks water. You can see the chart complete with all the information here, and TED-Ed has a great video that walks you through all the steps here.

So who keeps fish? The German. He lives in house 4, which has green walls, and he smokes Prince cigars and drinks coffee. Perhaps we may think of this German fish keeper as Einstein himself.