A TV presenter in Singapore recently posted a math problem on Facebook -- and the Internet is having trouble with the answer.
The logic problem was reportedly part of the Singapore and Asian Schools Math Olympiad, which is a competition for teens. After it was posted on Facebook, the puzzling math problem has been shared all over the world with people trying to solve it (and failing).
Here's the question:
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.
Cheryl 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?
Here's the answer (via Singapore's Study Room):
Following that statement, Bernard knows that May and June are ruled out.
Then, Bernard is able to know which month it is. So it must be either July 16, August 15 and August 17 (not 14th as then he can't know).
Since Albert subsequently can also be sure of the date, he must know it's July. If it's August, he can't be sure as there is August 15 and 17.
So the answer is July 16."
Did you answer correctly?
Here's another answer sheet on mothership.sg.
Copyright 2015 FOX 11 Los Angeles | Download our mobile app for breaking news alerts | Follow us on Facebook, Twitter and YouTube.