Singapore high school maths problem stumps Internet
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SINGAPORE: A maths problem that first appeared in a test for Singapore’s elite high school students has baffled Internet users around the world after it went viral, prompting a rush of attempts to solve it.
The question, involving a girl asking two boys to guess her birthday after giving them scant clues, first appeared in an April 8 test organised by the Singapore and Asian School Math Olympiads (SASMO).
It was meant for 15- and 16-year-old elite secondary school students, but swiftly went global after a local television news presenter posted it on his Facebook page Saturday. In the question, Cheryl gives her new friends Albert and Bernard 10 possible dates when they enquired about her birthday, before separately giving each of them further clues.
Test-takers are then asked to use logic to deduce Cheryl’s birthday using a short conversation between the two boys about the information given to them.
By Monday Internet users around the world were posting meticulously detailed answers to the puzzle on social media networks such as Facebook and Reddit, only to prompt a slew of comments disputing their findings and methodology.
Published in Dawn, April 15th, 2015
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Comments (35) Closed
Apr 15, 2015 06:41am
It is what is wrong with todays teachers who try to reinvent and some times stump themselves. It is not a maths problem but a request to be Psychic.
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Apr 15, 2015 06:54am
July 16 - Simples
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Apr 15, 2015 07:13am
It would have been better if DAWN had published the question and readers had given answers.
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Apr 15, 2015 08:03am
The answer is July 16
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Apr 15, 2015 08:05am
There is a possibility that there be a cut off date for admission to school and it could be May 15, June 17, July 14 and August 14. Go find out the date that new school year starts (school kids should know that cut off date to be admitted in the school year).
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Apr 15, 2015 08:28am
July 16 is the correct answer.
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Apr 15, 2015 08:41am
The solution as given on BBC and Aljazera assumes May is eliminated because 19 in unique and therefore not the solution and therefore the month itself is eliminated , whereas 16 is in both July and May . There are too many assumptions in the solution so NOT rigorous. Singapore hasn't invented anything of value , the test proves nothing .
Try the JEE tests especially the old ones , really tough and must be done in less than 2 minutes
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Apr 15, 2015 08:47am
Its simple and not a problem at all, not sure why they think it is difficult, this however suggests poor education standards .
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Apr 15, 2015 09:05am
Interesting problem, took me over 10 min to solve and my answer is 16 July!
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Apr 15, 2015 09:08am
Its July 16th
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Apr 15, 2015 09:11am
The answer is August 17th
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Apr 15, 2015 09:16am
Albert confirming that she is sure that Bernard is not aware means the month cannot be May and June because both have a unique date 19th and 18th respectively.
Bernard saying that he is sure after Albert's answer means that he has a unique date from the balance available dates.
So the answer is August 17.
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Apr 15, 2015 09:16am
July 16th??
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Apr 15, 2015 09:25am
the answer is July 16. This question is based on logic & deductions. amazingly confusing & thought provoking.
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Apr 15, 2015 09:28am
july 16
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Apr 15, 2015 09:41am
My view, B'day is on: August 17th.
Reason: If Albert does not know and knows that Bernard does not know either, then it cannot be June 18 or May 19. If it cannot be June 18, then Albert was told a month other than June, coz June 17 is the only other day remaining.
If it is not June 17 and Bernard now knows it is not June 17, the b'day must be Aug 17 (Bernard just got new information from Albert) that the Birthday is not in June. And since hearing this news, he was sure of the b'day, it can only be on Aug 17.
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Apr 15, 2015 09:51am
August 17 :)
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Apr 15, 2015 09:58am
Its may 19...as Bernard was given the date and albert knew that bernard knows the date...And then bernard says without asking albert the month, that now I know when her birthday is... and only date which is unique is 19th of may
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Apr 15, 2015 10:06am
Very interesting logic/maths question. The answer is July 16. Exclusion principle will apply here.
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Apr 15, 2015 10:18am
Its June 17th
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Apr 15, 2015 10:41am
Was that really a question for 16 yr old students????
It requires smart logic of Deductive Reasoning to applied.. not an easy one at all. 16 July is the answer btw.
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Apr 15, 2015 10:47am
The result can be deduced via logical successive elimination of unlikely events.
Its July 16 btw!
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Apr 15, 2015 11:19am
i know the right answer......
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Apr 15, 2015 11:21am
I think Cheryl is just stuck-up.
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Apr 15, 2015 11:23am
August 15th is the correct answer. But it is India's birthday not cheryls.
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Apr 15, 2015 11:27am
July 16
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Apr 15, 2015 11:37am
Answer is July 16 but its not simple. Those who are calling it simple, may I ask you to tell everyone how you got there and you didnt just google the answer.
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Apr 15, 2015 12:26pm
Lol. I dont know why people saying thats its easy. I had to read answer in detail for 10 mins then i understaood the answer. Here is the link to detailed answer
http://www.theguardian.com/science/alexs-adventures-in-numberland/2015/apr/13/how-to-solve-albert-bernard-and-cheryls-birthday-maths-problem
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Apr 15, 2015 12:38pm
why 2 guys who just befriended a girl want to know same time her birthday?..this doesnt make sense
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Apr 15, 2015 12:51pm
How the....What the.....
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Apr 15, 2015 04:49pm
Its simple. Albert knew its July so it has to be either 14th or 16th. Similarly, Bernard knew its 16th, so it has to be either May or July. Since July 16th is common between them, its the answer.
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Apr 15, 2015 06:30pm
@A. Khan How? Please explain.
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Apr 16, 2015 12:58am
Answer is quite simple:
Bernard initially does not know the answer but when Cheryl tells him the 'DAY' only, he knows exactly what her Birthday is meaning she told him either '18' or '19'. These two DAYs are appearing only once in the list and hence Bernard knew straight away what her Birthday is.
Similarly, when Albert came to know that Bernard 'NOW' knows her exact birthday by simply knowing the 'DAY' he can easily figure it out as he knows 'MONTH' as well.
So now both know her exact Birthday which is either 'May19' or 'June18'
Regards,
Shoaib
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Apr 16, 2015 10:32am
@bilal let me know how?
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Apr 16, 2015 10:35am
@A. Khan let me know how??
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