Brain Teasers

i.              Four prisoners got a golden chance to escape from prison if they answer correct but if they answer wrong then they have to die instantly when question asked by jailer. Jailer took them to the desert & buried their whole body inside the soil except for their head. They were arranged in way as shown in the figure below. The wall placed in between them can’t see the other side. Then he put white & black hats on their heads randomly. He said, “there are four hats; two black & two white on your head either it can be white or black hat on your head. Now any one of you can answer which hat you are wearing within 30 second. The condition is none can move their heads & none can produce sound. If you do so or if you don’t answer in time then you’d left alone & remain in this way forever.” Their life & death are determined after 30 second but fortunately one of the prisoner answers correctly in time.

Now the question is, who answer the question & what is the answer?

Answer: 3^rd prisoner answer he has white hat because he saw a black hat in front of him & thought that if his hat was black then the other prisoner behind him i.e 4^th prisoner must immediately answer that hat worn by 4^th prisoner is white since he already saw two black hats & must guess remaining hats were white. Instead the 4^th prisoner remained silent because he became confused seeing two different colored hats so 2^nd prisoner wearing black hat & 3^rd prisoner must be wearing white ones.

Sailesh Bataju

B.Sc 2^nd year