Five people, Albert, Bob, Terry, Christine, and Noah, each have one red hat on their heads from a pile that originally had two blue, two green, and five red hats. Each can see the others' hats but cannot see his or her own. Albert eventually deduces that he has a red hat on. How did he know? Assume that all five people are reasonably intelligent and logical. As long as you explain your though process and it's rational I don't see why it wouldn't be correct. So there might be more than one correct answer.