Home > Riddles > The three prisoners and the red hats
Three prisoners see each other's hats, but not their own. The key is not only in what each person sees, but in the silence of others.
Three prisoners perfectly logical are in row. Each one can ver the hats of the that has delante, but no the suyo nor the of quienes are behind.
The guard les says that each hat is red or blue, and that at least one of ellos is red. Les question, empezando by the last of the row, if can deducir the color of its propio hat.
The last responde that no. The second also responde that no.
Then the first deduce the color of the suyo. What color has its hat and how it knows?
Answer: his hat is red. Let us call the prisoners, from last to first, A, B and C. A sees the hats of B and C; B sees C's; C sees none. A says he doesn't know. If A had seen two blue hats, he would have known immediately that his was red, because the guard claimed that at least one was red. Since A does not know, B and C cannot both wear blue hats. B hears this and looks at C's hat. If B saw that C was wearing blue, then, since B and C cannot both be blue, B would deduce that his own hat is red. But B also says he doesn't know. Therefore, C cannot wear blue. So C deduces that his hat is red.
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