"The scholarship will be awarded," said the Head to the three candidates-Chuckles, Wombat, and Breeze--"to the winner in this little competition. I am going to chalk a cross, which will be either a green cross or a red cross, on the forehead of each one of you. I shall then ask each boy who can see a green cross to hold his hand up; and to take his hand down as soon as he can tell me what color his own cross is. He must, of course, be able to explain how his answer is arrived at. Kindly close your eyes for ten seconds." He chalked a green cross on all three foreheads. "Go!" All three hands shot up in the air; that of Chuckles was almost immediately lowered. "My cross is green, sir."
How did Chuckles know?

VIEW SOLUTION BELOW

THE SOLUTION

Call the candidates C, W, B. C argues as follows; Suppose my cross is red. Then W {or B} sees one green cross and one red cross. But W {like me} is a scholarship candidate and therefore intelligent. He will be saying; Suppose my cross is red. If it were, B would not have put his hand up, for he would be seeing two red crosses. Hence, if mine is a red cross, W {or B} should by this time have deduced that his own cross is green. It follows that my cross is green also. This is the logical solution. But I think that it is equally commendable if Chuckles makes this answer; The test, sir, would not be fair if two of us had green crosses and the third a red one