auntblabby wrote:
here is an answer I found online-
Albert knows the month and Bernard knows the day.
Albert knows the month. With the information he received, he can’t tell what her birthday is. However, he can tell with absolute certainty that Bernard does not know either.
(June) 18 and (May) 19 are the only dates with exclusive days. These get eliminated.
If the month is June, Albert wouldn't be certain that Bernard doesn't know either.
This means that all of June gets eliminated. For the exact same reason, all of May gets eliminated as well.
This leaves the dates in July and August.
Now it's Bernard's turn. He confirms that he at first did not know, however with this new information, he is now certain of her birthday.
If the day he got was the 14th, Bernard would still doubt between July and August. July 14th and August 14th get eliminated.
This leaves the 15th of August, the 16th of July and the 17th of August. Bernard either got the number 15, 16 or 17.
It's Albert's turn again. Knowing that Bernard now knows her birthday, he is now also absolutely certain of the date as well.
If the month Albert got was August, he would still doubt between the 15th and the 17th. The 14th of July was previously eliminated by Bernard. This only leaves the 16th of July.ok, now for some questions of my own-
WHY EXACTLY are the exclusive days of may 19/june18 automatically eliminated? WHY are july 14/aug 14th eliminated?

I have gathered so far, that to solve this, one must have a higher-than-average capacity working memory which equals high IQ.
May 19 and June 18 are eliminated because Albert knows for certain that Bernard does not know her birthday. If Bernard was told "19" then he would know it was May, if he was told "18" then he would know it was June, as there are no other options. Albert was told one of the other two months, because if he was told "May" or "June", he couldn't know for certain that Bernard doesn't know her birthday (i.e. that he wasn't told "19" or "18").
Both of the 14ths are eliminated because after Bernard hears Albert say that he knows Bernard does not know her birthday, he now knows that it must be July or August (due to the logic above). Bernard now knows her birthday, which means he isn't still confused between July or August. The 14th appears in both of those months so it can't be the 14th, or he wouldn't be certain.
Finally, after Albert hears that Bernard is certain, the only way Albert can also be certain is if there is only one date remaining. July is the only month with only one date remaining.
Maybe I just reworded what was already said above, but hopefully I've said it in a way that clarifies it a bit more