What Colour is my hat?
They are sat in a row like in the picture, Their father then puts either a red or blue hat on their heads. Alice can see Bob and Charlie's hat. Bob can see Charlie's hat. And charlie can see none of the hats. None of them can see his own hat.
Their father puts hats on each of their heads and says: "Each of your hats is either red or blue, two of you who are seated adjacently (beside each other) both have red hats" Alice then says: "I don't know the colour of my hat" Which of them has the Red hat?