There are five caps , 3 black and 2 white. Three persons Walker, Hall and Allen are standing one behind the other in a queue. The first person in the queue is Walker and the last person is Allen . 3 caps from the five has been taken and put on their heads. Allen can see what the other two standing in front are wearing . Hall can see what Walker is wearing. None of them can turn around and see what the person standing behind is wearing , they do not know the color of cap what they themselves are wearing . John comes and asks Allen,"What is the color of the cap your are wearing?", Allen can see what Hall and Walker are wearing, and based on that he says he doesn't know. Hall has over heard that answer. Now john asks Hall what is the colour of the cap you are wearing". Hall can see Walker and he has heard what Allen has said, and based on that he says he doesn't know. Walker has overheard both Hall and Allen. so when john asks Walker the same question, he tells the correct answer. What is the colour of the cap that Walker is wearing ? write in brief how did you reach to that conclusion ?