In this TED-ED video, we're presented with what's called "Einstein's Riddle." As the video-makers admit, it apparently has nothing to do with Einstein, aside from being a fairly tough puzzle to crack. If you enjoy logic puzzles, you'll want to set aside ten minutes for this one!
"Einstein's Riddle" is a form of Zebra Puzzle, in which you're provided with a series of facts, then asked to deduce one fact that's not presented. In the video's case, it's the location of a fish that has been kidnapped. There are five identical houses in a row (numbered one through five), and one of them contains the fish. Can you figure out which house it is, with only the clues provided?
If you're not in a place to check out the video, here are the starting assumptions:
1. Each house's owner is of a different nationality (German, Norwegian, Danish, British, Swedish); drinks a different beverage (tea, milk, coffee, root beer, water); and smokes a different brand of cigar (Pall Mall, Prince, Blends, Dunhill, Blue Master). 2. Each house's interior walls are painted a different color (blue, green, yellow, red, white.) 3. Each house contains a different animal (horse, dog, cat, bird, fish). You're looking for that fish!
And here are all the clues:
1. The Brit lives in the house with red walls. 2. The Swede has a dog. 3. The Dane drinks tea. 4. The house with green walls is directly to the left of the house with white walls. 5. The owner of the house with green walls drinks coffee. 6. The person who smokes Pall Mall cigars owns a bird. 7. The owner of the house with yellow walls smokes Dunhill cigars. 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 cat owner. 11. The horse's owner lives next to the man who smokes Dunhill. 12. The man who smokes Blue Master drinks root beer. 13. The German smokes Prince. 14. The Norwegian lives next to the house with blue walls. 15. The man who smokes Blends has a next-door neighbor who drinks water.
Can you figure out which of the five houses has the fish?