You are a spy in a hostile country, trying to escape the local authorities. As a disguise, you join the local Knavy, which is like a navy, but is made up entirely of knaves (people who alternate telling the truth and lying). You get word that a ship, the HMS Levik is docked in the harbor to help you escape. The problem is, there are five ships in port (at docks one through five) and none of them are marked with a name.
  You manage to talk with two old sea captains in the Knavy about which ship is which. They talk some, but you don't know if their first statement is a truth or a falsehood.
  Based on their curious descriptions, can you figure out which ship is the HMS Levik?

CAPT. HUDSON:
1. The Salamander is not moored next to the Revenge.
2. The Antimony is moored at dock one.
3. The Levik is moored at dock two.
4. The Defiance is moored next to the Levik

CAPT. BAFFIN
1. The Defiance is not moored at dock two.
2. The Levik is moored at dock four.
3. The Salamander is moored next to the Revenge.
4. The Antimony is not moored next to the Salamander.

 

If B2 (Levik at 4) is true then B1 is false meaning Defiance IS at 2. Since Levik and Defiance aren't next to each other than H4 is wrong meaing h3 must be true (nature of a knave). Since H3 conflicts with assumption than Levik is not 4 and we know that B2 is false so we know which Baffin statements are true and false. Since B3 is true we know that H1 is false which means H2 is true. The Antimony is at 1.

1: Antimony

B4 is false so the Antimony is next to the Salamander.

2: Salamander

B3 is true so the Salamander is next to the Revenge

3: Revenge

B2 is false so the Levik is not at 4 and only 5 is left

Answer: Levik is in 5th dock

BTW, we not only can find where the Levik is, but where all the ships are.

Posted by Rajal on 2004-08-05 10:18:15