>>newuser If you think his answer is correct, then why do u ask me for the correct one ? I am just a poor student (no need to call me a 'Sir') and my rejecting or accepting any answer doesn't make it right or wrong.You should have the ability to judge the validity of a proof yourself. I gave my opinion. If you don't like it curse me or something. As for Nirman's proof, I gave a reason why it is wrong. If he comes up with the right one , I don't have any personal reasons to say that he is wrong. He is a decent Sajha basi and I am a huge fan of his literary works as well. >'Reynolds thought about this and finally told Craig whether or not he knew whether he could have decided had the other one answered the second question instead. ' > Arch Sir, I think the above sentence concludes that one amongst A and B is a kinght and the other is knave. So there is no possibility of them being knight, knight or knave, knave as you suggest. No , it doesn't. To tell u the truth, Reynold can deduce that A is a Knight but he doesn't have enough information to find whether B is a Knight or a Knave and hence the answer he gave to Craig. Not because one was knight and the other was knave, as you said but because he knew the identity of one and not of the others.