-Albert and Bernard just friends with Cheryl and they wanted to know his birthday . Cheryl then give 10 options , namely :
May 15, May 16 , May 19 June 17, June 18 July 14, July 16, August 14, August 15, and August 17
-Then , Cheryl told Albert and Bernard separately on the month and date of his birthday sequentially .
-Albert and Bernard then made a statement :
Albert : I do not know when Cheryl 's birthday , but I'm sure Bernard does not know well .
Bernard : At first I did not know Cheryl 's birthday , but I now know .
Albert : It means I also know Cheryl 's birthday .
So when Cheryl 's birthday ?
--source : Kenneth Kong --