I used to quite enjoy doing those logic problems that were popular when I was an adolescent and a couple of days ago I came across one that is similar to those but for some reason has captured the imagination of the inhabitants of the internet and has been discussed widely. Here it is:
Albert and Bernard just met Cheryl. “When’s your birthday?” Albert asked Cheryl.
Cheryl thought a second and said, “I’m not going to tell you, but I’ll give you some clues.” She wrote down a list of 10 dates:
May 15 — May 16 — May 19
June 17 — June 18
July 14 — July 16
August 14 — August 15 — August 17
“My birthday is one of these,” she said.
Then Cheryl whispered in Albert’s ear the month — and only the month — of her birthday. To Bernard, she whispered the day, and only the day.
“Can you figure it out now?” she asked Albert.
Albert: I don’t know when your birthday is, but I know Bernard doesn’t know, either.
Bernard: I didn’t know originally, but now I do.
Albert: Well, now I know, too!
When is Cheryl’s birthday?
With most logic puzzles of this type, once the answer is figured out or revealed, people tend to agree that it is correct. But apparently there has been a controversy over this one which I don’t understand since the solution seems unambiguous to me.
The real issues over which there could be some contention involve the social dynamics on display here. For example, would you like to have Cheryl as a friend? She seems to be one of those annoying people who likes to complicate even the most mundane things and it would not surprise me if Bernard and Albert decided that if this is how she responds to a simple question at a first meeting, then being friends with her would be too much work.
On the other hand, it seems a bit presumptuous on their part to ask Cheryl when her birthday is when they had just met her and she may have responded that way to signal that it was inappropriate. Or maybe I am just out of touch with contemporary conversational starters among the younger generation.
All in all, I would give all three of them a wide berth.