>>>There are three men on a deserted island.
>>>The men on the island are either Red or Blue.
>>>
>>>Red people always tell lies.
>>>Blue people always tell the truth.
>>>
>>>A ship comes to rescue them and the captain of the ships shoult to the men, "We will only rescue Blue people."
>>>
>>>Man A says, "I'm blue and those two are "red".
>>>Man B says something but it was blown away with the wind.
>>>Man C Says, "B said he's Blue. That's true. I'm blue too."
>>>
>>>Which of the three men should take if he wants just blue people and why?
>>
>>He should take B & C. A told the false (e.g. he is actually red and other two are blue). C said the truth.
>
>That's mostly correct, but what exactly about C's statement makes it the truth?

Suppose, C is a liar.

This would mean, that B said, he is Red. If B is Blue, he woud say, he is Blue. If he is Red, he would also say, he is Blue, so if C is a liar, he would say, that B said, he is Red.