A Math problem, earlier thought to be intended for Primary 5 students in Singapore has gone viral after it was posted by “Hello Singapore” TV presenter Kenneth Kong on his Facebook on Saturday, April 11.
Kong captioned his post: “This question causes a debate with my wife… and it’s a P5 question.” It has since been shared more than 5,000 times and widely circulated across the world, baffling many netizens for its complex but doable solution.
The question was:
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 15 May 16 May 19 June 17 June 18 July 14 July 16 August 14 August 15 August 17
Cheryl then tells Albert and Bernard separately the month and the day of her birthday respectively.
Albert: I don’t 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?
After the post went viral, the executive director of Singapore and Asean Schools Math Olympiad (SASMO), Henry Ong clarified the question was actually a problem for Section 3 and 4 in the Math Olympiad last April 8.
Ong said it was a “difficult question meant to sift out the better students”, and is the 24th in the list of 25 problems. He said he felt the need to clear things out so Singaporean parents need not worry unnecessarily.
Ong added the questions were devised by math experts and professors in Singapore and from other countries.Nevertheless, for those who are wondering when is Cheryl’s birthday, here is an explanation from SASMO as published by the Guardian: (Click here to find the answer)