The Islanders

Logic Level 1

There are two beautiful yet remote islands in the south pacific. The Islanders born on one island always tell the truth, and the Islanders from the other island always lie.

You are on one of the islands, and meet three Islanders. You ask the first which island they are from in the most appropriate Polynesian tongue, and he indicates that the other two Islanders are from the same Island. You ask the second Islander the same question, and he also indicates that the other two Islanders are from the same island.

Can you guess what the third Islander will answer to the same question?

Image credit: Wikipedia Fanny Schertzer

No, the third Islander will not say the other two Islanders are from the same island. The third Islander will not answer anything inadequate information Yes, the third Islander will say the other two Islanders are from the same island.

4 solutions

Feathery Studio
Jul 4, 2015

If the first person was a truthteller, then the other two are from the same island, if he's a liar, the other two are from different islands.

So we have 4 combinations

$TTT$

$TLL$

$LTL$

$LLT$

Of the four combinations, if a truthteller is the last person, the other two are the same, so he would say, "yes, the other two are from the same island." If a liar is the last person, the other two would be from different islands, but lying, he would say, "yes, the other two are from the same island."

Either way, the third person will say " $\boxed{yes}$ ."