bodyType

customContents

entityId

entityUuid

articlePageQuery

filter

article

articleBaseAdvertisingInfoArticle

articleListArticle

articleSeoArticle

hooksArticleAcknowledgementGateOverlayArticle

hooksTrackPageViewArticle

hooksContentInterestArticle

articleLinkingDataContent

hooksAmpRedirectArticle

articleSchemaContent

liveArticle

advertZone

sentiment

contentLock

topics

types

sections

paywallTypes

createdDate

publishedDate

urlAlias

moreOnThisArticles

sponsorType

commentCount

authorLocations

authors

corrections

displaySlideShow

multimediaEmbed

printHeadline

seriesContainer

articleSpeeches

socialHeadline

headline

images

flag

firstTopic

glossary

flattenTypeIds

image

relatedLinks

relatedNewsletters

__typename

sponsor

pdfFiles

seriesReverseOrder

series

disableOffPlatformContent

published

updatedDate

summary

subHeadline

body

keywords

readingTime

customTimezone

liveContents

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 seemingly scant clues, first appeared in an April 8 test organised by the Singapore and Asian School Math Olympiads (Sosma).
It was meant for elite secondary school students aged 15 and 16, 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, a list of 10 possible dates for her birthday - May 15, 16 or 19; June 17 or 18; July 14 or 16; and August 14, 15 or 17. Separately, she tells Albert the month of her birth, and Bernard the date. A conversation ensues.
"I don't know when Cheryl's birthday is, but I know that Bernard does not know too," Albert explains.
Bernard responds: "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."
Test-takers are then asked to use logic to deduce Cheryl's birthday from the conversation.
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.
Sosma later provided the full question and a model answer.




Singaporean high school logic puzzle sets internet abuzz after going viral

The question, involving a girl asking two boys to guess her birthday after giving them seemingly scant clues, first appeared in an April 8 test organised by the Singapore and Asian School Math Olympiads (Sosma).

In a Facebook post late Monday, SOSMA provided the full question and a model answer.