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Of brevity, expression and logical analysis

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BRAIN TEASERS: Solving puzzles helps sharpen the mind.
BRAIN TEASERS: Solving puzzles helps sharpen the mind.

Take on students' test of nerves

Two puzzles were given last week and prizes were announced.

The first puzzle deals with “two black and three white hats”. Three people were buried and were asked to identify the colour of the hat on their heads. If at least one succeeds, all would be released. The next riddle is: A king, minister and eight soldiers are asked to stand in a queue, and either red or blue hat is placed on each head. The last person is asked by the rivals to identify his hat. If he is wrong, he would be killed on the spot. Then rivals turn to the second one from the last. The Minister tells a clue to others and stood last. Fortunately, he could save himself “by chance”. But all others are saved with his clue. How? Answers: The first puzzle can be solved in three stages: Step one: The last person sees two hats before him. If they are both black, without hesitation he declares that his hat is white. His silence denotes that he is seeing either 2 white (or) 1 white and 1 black hat. Step two: The middle person recognises this fact and if he sees a black hat before him he would immediately realise that his hat is white. He does not do so which means he is seeing a white hat. Step three: The first person understands his silence and says, “Mine is white”. The second riddle is more complicated. The minister attributes “value” to the colour of their hats (Red Hat =1 and Blue Hat = 2). The last prisoner should add up values of all the 9 hats before him and if the total is an even number, he should say ‘blue’, or if it is an odd number, he should say ‘red’. Minister takes the risk of his life to save others. Suppose he finds 3 red and 6 blue hats before him, the value of the hats is (3X1) + (6X2) = 15. It is an odd number and hence he says his hat colour is “red”. He is fortunate to guess it correctly. Now the soldier in front of the Minister knows that the value of all 9 hats (including his) is 15. He totals the value of remaining 8 hats standing before him. If it is 13, his hat is ‘blue’ and if it is 14, his hat is ‘red’. Five winners are chosen for brevity, expression, logical analysis .

Yandamoori VeerendranathYandamoori@ hotmail.com

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