Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates.
May 15 June 17 July 14 August 14 May 16 June 18 July 16 August 15 May 19 August 17
Cheryl then tells Albert and Bernard separately the month and the day of her birthday respectively.
Albert says that he does not know when Cheryl’s birthday is, but he knows Bernard doesn’t know either. Bernard says that he first didn’t, but know he knew. Then Albert says he knows when her birthday is.
So how do you know when is her birthday? (Search Cheryl riddle on the internet) I don’t get the explanation.