Island Dilemma: Choosing the Right Path Based on One Question

[forgingiron]

1. Homework Statement
You are on an island, and you reach a fork in the road. You want to go to the Cuddly-Wuddly tribe, not the Nasty-wasty tribe. Cuddly-Wuddlies always tell the truth, while Nasty-Wasties always lie. A man is standing in the middle of the road, but you don't know what tribe he's from. You can only ask 1 question; what question do you ask to know which way to go?

Homework Equations

None. I just got this in math class, that's why it's in this forum.

The Attempt at a Solution

Ask if he was of the other tribe, which way leads to the Cuddly-Wuddly tribe, go the other way. The closest guess in the class is to ask which way is NOT the Cuddly-wuddly tribe.

 

[HallsofIvy]

1. Homework Statement
You are on an island, and you reach a fork in the road. You want to go to the Cuddly-Wuddly tribe, not the Nasty-wasty tribe. Cuddly-Wuddlies always tell the truth, while Nasty-Wasties always lie. A man is standing in the middle of the road, but you don't know what tribe he's from. You can only ask 1 question; what question do you ask to know which way to go?

Homework Equations

None. I just got this in math class, that's why it's in this forum.

The Attempt at a Solution

Ask if he was of the other tribe, which way leads to the Cuddly-Wuddly tribe, go the other way. The closest guess in the class is to ask which way is NOT the Cuddly-wuddly tribe.

I think what you really meant was: ask "If I were to ask a person of the other tribe the way to the Cuddly-wuddly tribe, what would he answer?", then go the other way.

Yes, that works. If the person is of the Cuddly-wuddly tribe, the other tribe is the Nasty-wasty tribe and would point the wrong way. The person of the Cuddly-wuddly tribe would answer your answer truthfully by pointing the wrong way.

If the person is of the Nasty-wasty tribe, the other tribe is the Cuddly-wuddly tribe and would point the correct way. A person of the Nasty-wasty tribe would answer untruthfully by pointing the wrong way.

In either case, the person is would point the wrong way. Going the other way leads to the Cuddly-wuddly tribe.

Now, excuse me. Having written "Cuddly-wuddly" and "Nasty-wasty" so many times, I need to go fwow-up.

 

[romolo]

I think the following question would work too. It is simpler...

"Which way is your tribe?"

Either way, the man points to the Cuddly-Wuddly tribe, yes?

 

[HallsofIvy]

Ouch! That's embarassing.