Tuesday, April 14th, 2015
Social media has been going nuts over the logical puzzle of Albert and Bernard trying to figure out Cheryl’s Birthday. It seems to be the next big thing after THE DRESS. While THE DRESS was something I had no clue about, this problem is simple enough. Apparently, it is simple enough for 5th graders in Singapore as well – but let’s not get into that discussion.
 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 15Â Â Â Â Â Â Â Â Â Â Â Â May 16Â Â Â Â Â Â Â Â Â May 19
June 17Â Â Â Â Â Â Â Â Â Â Â Â June 18
July 14Â Â Â Â Â Â Â Â Â Â Â Â July 16
August 14Â Â Â Â Â Â Â Â Â August 15Â Â Â Â Â Â August 17Cheryl then tells Albert and Bernard separately the month and the day of her birthday respectively.
Albert: I do not know when Cheryl’s birthday is, but I know that Bernard does not know too.
Bernard: At first I don’t know when Cheryl’s birthday is, but I know now.
Albert: Then I also know when Cheryl’s birthday is.
So when is Cheryl’s birthday?
If you want a quick and dirty solution (basically something that can come in a tweet):
S1 eliminates May & June
S2 eliminates Date 14
S3 eliminates Aug
Answer is July 16
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[…] All those nocturnals out there and puzzle enthusiasts keep calm and take up the gauntlet. And cross check it with Mr. Handa’s solution here. […]