This is the second part of the solution for the problem which I provided a couple of days ago. If you have not read this then please start from the first part of this problem – When is Cheryl’s birthday.
Yesterday I provided the first hint to you, and we concluded with the following:
STATEMENT 2: Albert: I don’t know when Cheryl’s birthday is, but I know that Bernard does not know too.
The question to ask is: how does Albert KNOW that Bernard does NOT KNOW the birthday!
We can also ask this another way – HOW could Bernard KNOW the birthday, and how would Albert also KNOW that Bernard KNOWS?