'When is Cheryl's Birthday?' - Singapore's Math Problem Baffles the World

"When is Cheryl's Birthday?" the Singaporean math problem which became viral in social media due to its difficulty in nature which calls a student to think like Sherlock Holmes???

BBC news reported that "When is Cheryl's Birthday?" is a school math question posted on Facebook by a Singaporean TV presenter has baffled thousands, and left many asking if that's really what is expected of Singaporean students.

Initial report said that the math examination question is for 11 years old students.

In Singapore, students stressed by tough examinations is a perennial and Cheryl's Birthday reignited concerns that the education system was too challenging.

Later, it was found out that the math question which 'stumped a million minds' is for 15-year old students who joined last week's Singapore and Asian Schools Math Olympiads (SASMO).

SASMO organizer said the test was aimed at the top 40% and aimed to "sift out the better students", adding it was "important to clarify so that Singapore parents will not start to worry so much".

Curious about the viral math question, 'When is Cheryl's Birthday?'? Check the image that follows...

I hardly get the logic question and it's up to you to answer this question.

When is Cheryl's birthday? Try figuring out the answer without using the internet. You may leave your answer and explanation in the comment box.