On an island where knaves never tell the truth and knights always tell the truth, you meet 3 of the island's inhabitants: Fred, George, and Quincy. You ask Fred, "Are you a knave?" Fred says the answer to the other natives, but you can't hear him. George turns to you and says that Fred denied being a knave. Quincy says Fred is a knave. 

How many of the three are knaves? 

 

Answer:

• For this scenario, despite the fact that you did not get to hear what Fred replies,Quincy claims that Fred denied being a Knave. If indeed he is a knight, then he would instinctively tell the truth and state "NO", that he is not a knave. In the instance that he is indeed a knave, then he would claim not to be a knave. This therefore implies that him being a knave or even a knight will result in a "NO" response that denies that he is a knave in every scenario.

• George on the other hand claims that Fred denies that he himself is a knave. This basically tends to be true and instinctively implies that George is a knight.

• Quincy claims that Fred is a knave. If indeed Quincy is a Knight, then this implies that Fred is himself a knave. This has the implication that there are two knights, one being Quincy and the other being George. The other remaining person, Fred is thus a knave.  
• If for a fact Quincy is a knave, he is indeed lying, meaning that Fred is not a knave and is himself a knight. This instance showcases the presence of two knights, one being Fred and the other being George, and one knave, who is Quincy.

This can be concluded that despite the fact that there is the knowledge of George being a knight, for every set scenario there is the prospect of two knights with one knave. This in itself falls down to "If Quincy is a knight, then Fred is also knave", and "If Quincy is a knave, then Fred is also a knight".