# Cheryl's Birthday: Singapore's maths puzzle baffles world

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A school maths question posted on Facebook by a Singaporean TV presenter has stumped thousands, and left many asking if that's really what is expected of Singaporean students.

The question asks readers to guess the birthday of a girl called Cheryl using the minimal clues she gives to her friends, Albert and Bernard.

Cheryl's Birthday was initially reported to be an examination question for 11-year-olds.

Students stressed by tough examinations is a perennial issue here, and Cheryl's Birthday reignited concerns that the education system was too challenging.

How to solve: https://youtu.be/KlYxH1XJquY

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After getting past the Singlish, it was pretty easy to solve.

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actually it was for Country Maths Olympics students, hardly you average kid.

also for 14 year olds..!

not for your 11 year olds average school kids, obviously!

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Flawed riddle. It is impossible for Albert to know what he claims to know. It does NOT say Cheryl told Alberta that Bernard does NOT know the birthday. How would Alberta know this? QUOTE: "Cheryl tells the month to Alberta and the day to Bernard". This is the only info Cheryl told them.
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Flawed riddle. It is impossible for Albert to know what he claims to know. It does NOT say Cheryl told Alberta that Bernard does NOT know the birthday. How would Alberta know this? QUOTE: "Cheryl tells the month to Alberta and the day to Bernard". This is the only info Cheryl told them.

NO

Thought-process-only solution

All Albert needs to know to be able to make his first statement is the knowledge that the month he was given does not contain a unique day. That fact that he made his statement means that the month Cheryl gave him was one of the months which does not contain a unique day, therefore meaning that it is impossible for Bernard to know Cheryl's birthday at this point.

With the months that do not contain a unique date now having been eliminated, Bernard claims that he now knows Cheryl's birthday. The fact that he can say this means that he must have been given a day which only occurs once among the remaining months.

After hearing that Bernard now knows the answer, Albert says that he now knows the answer too. This means that the month he was given must contain only one of the numbers that occur only once among the remaining months.

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Perhaps if it were presented better it wouldn't be so confusing. I didn't solve it and I know I wouldn't have solved it at 11, but I do know that if I read it at 11, I would have thought "who wrote this crap?"

Overall, I like it.