Using the Einstein’s Logic Riddle to find good (and smart) people?

Inspired by: http://www.brain-fun.com/Brain-Teasers/EinsteinsRiddle.php Einstein’s Riddle: Einstein believed that 98% of people could not solve the following logic riddle. Wouldn’t it be interesting to use this as a hiring tool, not so much to make sure your candidate has the answer – although it would surely be nice – but to see how they will approach solving a problem. Here’s the riddle: There are 5 houses each with a different color. Their owners, each with a unique heritage, drinks a certain type of beverage, smokes a certain brand of cigarette, and keep a certain variety of pet. None of the owners have the same pet, smoke the same brand of cigarette or drink the same beverage. Clues:

• The Brit lives in the red house.
• The Swede keeps dogs as pets.
• The Dane drinks tea.
• The green house is just to the left of the white house.
• The green house’s owner drinks coffee.
• The person who smokes Pall Malls raises birds.
• The owner of the yellow house smokes Dunhill.
• The man living in the center house drinks milk.
• The Norwegian lives in the first house.
• The man who smokes Blends lives next to the one who keeps cats.
• The man who keeps a horse lives next to the man who smokes Dunhill.
• The owner who smokes Bluemasters also drinks beer.
• The German smokes Prince.
• The Norwegian lives next to the blue house.
• The man who smokes Blends has a neighbor who drinks water.

Who owns the fish?

<- – - end of riddle – - – >

One way to arrive to the solution is to find those absolute statements that give the most significant information. I re-wrote the statements as follows:

1. The Brit lives in the red house.
2. The Swede keeps dogs as pets.
3. The Dane drinks tea.
4. The green house is just to the left of the white house.
5. The green house’s owner drinks coffee.
6. The person who smokes Pall Malls raises 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 a horse lives next to the man who smokes Dunhill.
12. The owner who smokes Bluemasters also 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.

Also, I called the the first house 1, the second 2, etc. . . we have that:

• Statement I tells us the Norwegian lives in house # 1
• Therefore according to statement N, house #2 must be Blue.

1	2	3	4	5
	Blue
Norwegian

• Statement H tells us the house # 3 drinks coffee;
• Let’s combine statements D and E. D tells us that the Green house and the White house are next to one another, with Green being on the left, and Green drinks coffee. The only possible location that fits these criteria is Green on house # 4 and White on House # 5.

1	2	3	4	5
	Blue		Green	White
Norwegian
		Milk	Coffee

• Now the easiest next step is to complete the color allocation, we have only Red and Yellow to assign, and only house #1 and #3 without color assignment. Statement A tells us that the Brit lives in the red house. Since we already know that the Norwegian lives in house # 1, house # 3 is the only one who can satisfy statement A.
• Conversely House #1 must be Yellow and according to Statement G, the owner must smoke Dunhill, and statement K tells us that house #2 has a horse.

1	2	3	4	5
Yellow	Blue	Red	Green	White
	Horse
Norwegian		Brit
		Milk	Coffee
Dunhill

• By combining statements J and O, we can see that the person who smoke blends can only be living in house # 2 or # 3. While looking at statement L, we can see that whomever Smokes Bluemaster and Drink Beer can live either in house #2 or house #5, and the only combination that satisfies J, O, and L is for the owner of house # 2 to smoke Blend (and therefore the Norwegian in house #1 to drinks water), and the owner of house #5 to smoke Bluemasters and drink beer.

1	2	3	4	5
Yellow	Blue	Red	Green	White
	Horse
Norwegian		Brit
Water		Milk	Coffee	Beer
Dunhill	Blend			Bluemaster

• The easiest set to complete now is the “drink” set, with house # 2 being the only one that can accommodate statement C.

1	2	3	4	5
Yellow	Blue	Red	Green	White
	Horse
Norwegian	Dane	Brit
Water	Tea	Milk	Coffee	Beer
Dunhill	Blend			Bluemaster

• House #4 is the only one that satisfies statement M of the relationship between nationality and cigarette

1	2	3	4	5
Yellow	Blue	Red	Green	White
	Horse
Norwegian	Dane	Brit	German
Water	Tea	Milk	Coffee	Beer
Dunhill	Blend		Prince	Bluemaster

• Let’s now complete the cigarette set by applying statement F

1	2	3	4	5
Yellow	Blue	Red	Green	White
	Horse	Birds
Norwegian	Dane	Brit	German
Water	Tea	Milk	Coffee	Beer
Dunhill	Blend	Pall Mall	Prince	Bluemaster

• Having placed “birds” in House #3, we can now apply statement J

1	2	3	4	5
Yellow	Blue	Red	Green	White
Cats	Horse	Birds
Norwegian	Dane	Brit	German
Water	Tea	Milk	Coffee	Beer
Dunhill	Blend	Pall Mall	Prince	Bluemaster

• We are now left applying statement B

1	2	3	4	5
Yellow	Blue	Red	Green	White
Cats	Horse	Birds		Dogs
Norwegian	Dane	Brit	German	Swede
Water	Tea	Milk	Coffee	Beer
Dunhill	Blend	Pall Mall	Prince	Bluemaster

• Leaving only the German who lives in the Green House #4, smokes Prince, and drinks coffee as the only possible owner of FISH!

1	2	3	4	5
Yellow	Blue	Red	Green	White
Cats	Horse	Birds	FISH	Dogs
Norwegian	Dane	Brit	German	Swede
Water	Tea	Milk	Coffee	Beer
Dunhill	Blend	Pall Mall	Prince	Bluemaster

Al, eat your fish out! P.S.: solved using the classic whiteboard and color markers

Tagged as: Creativery