Zebra Problem The problem – Who Owns the Zebra – is a classic problem in logical deduction. The elements of the problem require you to identify each item with a house. House • Beverage • Color • Nationality • Pet • Occupation
COT-3100 – Zebra Problem • Who owns the zebra? – attributed to Albert Einstein. • Five men of different nationalities, with different jobs, live in consecutive houses on a street. These houses are painted different colors. The men have different pets and have different favorite drinks. • Determine: who owns the zebra and whose favorite drink is mineral water. • Here are the clues: • The Englishman lives in the red house. • The Spaniard owns a dog. • The green house is on the right side of the white house. • The Italian drinks tea. • The Norwegian lives in the first house on the left. • The photographer breeds snails. • The Norwegian’s house is next to the blue one. • The Japanese man is a painter. • The fox is in a house next to that of the physician. • The diplomat lives in the yellow house. • The owner of the green house drinks coffee. • The violinist drinks orange juice. • The horse is in a house next to that of the diplomat. • Milk is drunk in the middle house.
Zebra Problem House • Beverage – Coffee Milk O.J. Tea Water • Color – Blue Green Red White Yellow • Nationality – Englishman Italian Japanese Norwegian Spaniard • Pet – Dog Fox Horse Snail Zebra • Occupation – Painter Photographer Physican Diplomat Violinist Each item is treated as an EXCLUSIVE OR within its category
COT-3100 – Zebra Problem Symbolically representing the relationships, and the NOT relationships: Violinist O.J. Spaniard Dog Japanese Painter Italian Tea Norwegian House 1 White Green (R) Photographer Snails Norwegian Blue (next) Milk House 3 Green Coffee Yellow Horse (next) Englishman Red HousePhysician Fox (next) Diplomat Horse (next) Diplomat Yellow Spaniard | Photographer Italian | House 3 Englishman | Coffee Englishman | Blue Englishman | House 1/2 Japanese | Photo Italian | Green Japanese | Violinist Blue House 2
COT-3100 – Zebra Problem Color: Blue Green Red White Yellow Nationality: Englishman Italian Japanese Norwegian Spaniard Pet: Dog Fox Horse Snail Zebra Beverage: Coffee Milk O.J. Tea Water Occupation: Painter Photographer Physician Diplomat Violinist
COT-3100 – Zebra Problem Plotting known elements: Plotting elements that are eliminated from each house:
COT-3100 – Zebra Problem Results and/or possibilities (from eliminations) Italian Violinist/Physician Spaniard Violinist/Physician :Englishman Photographer
COT-3100 – Zebra Problem Spaniard Violinist O.J White
COT-3100 – Zebra Problem The ZEBRA problem is an excellent exercise in logic flow. It is also a 5 x 5 matrix, and makes an excellent project for computer analysis.