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(6) Three logicians, A, B, and C, are nvited to play a curious game. From a coll

ID: 3196020 • Letter: #

Question

(6) Three logicians, A, B, and C, are nvited to play a curious game. From a collection of four green and four red stamps, two will be pasted on each of their foreheads, and the remaining two will be hidden from all. Each logician be able to see the stamps on the other two, but not his own forehead. First, A is asked what is on his forehead, and he says he does not know. Then B is asked what is on his forehead, and he says he does not know. Then C is asked, and also says he does not know. A is asked again, and he says he does not know. Then B is asked. What is his answer?

Explanation / Answer

Let R stand for red stamp and G for the green one.

The 1st thing we need to rule out certain possibilities for the above mentioned case to occur(i.e B answering in 2nd turn).