Originally posted by Duchess64
Here's a recreational mathematics problem that recently 'went viral':
"Can you solve the maths question for Singapore schoolkids that went viral?"
--Alex Bellos (13 April 2015)
(The problem was given to t ...[text shortened]... problems when I was younger.)
Have fun trying it before looking up a solution on the internet.
Fairly straightfoward solution:
Albert: "I don't know the date, and I know Bernard doesn't know it either"
Albert knows that the month of the birthday cannot have a day in it that is unique, therefore, no May or June
Bernard: "I didn't know before, but now I do."
This eliminates the 14th as the day, leaving only July 16, August 15, and August 17
Albert: "Then I also know the date"
It must be July 16, since Albert could not have a solution if the day was in August