In a remote island, all the inhabitants are either knights, who always speak truthfully or liars, who always speak falsely.

Ten natives of the island are engaged in a conversation. A visitor from a nearby island approaches the natives and, asks them: "How many of you are knights?"

Each of the ten natives answer in turn: 3, 2, 5, 7, 3, 0, 4, 4, 3, 5

In reality, how many of the ten natives are knights?

All one needs to do is look for the answer, "n", that is repeated exactly "n" times.  "n" Knights must say "n".  The Liars cannot say "n".  Therefore, the answer must be 3.

BTW - this is true whether they speak in turn, or shout it out all at once.

Posted by Kenny M on 2012-08-27 19:05:27