A Question From A Fifth Grade Math Test Is Completely Stumping The Internet. Can You Figure Out the Answer?
Are you smarter than a fifth grader? How about a fifth grader in Singapore?
A question that appeared on the Singapore and Asian Schools Math Olympiad test for “Primary 5″ students has many on the internet completely baffled – and now the question is going viral.
Facebook user Kenneth Jianwenz posted the photo April 10. It asks students to figure out when “Cheryl” has her birthday based on the numbers “Albert” and “Bernard” are given.
Albert was given one number associated with the month of Cheryl’s birthday while Bernard was told the number associated with the correct day of the month.
Albert says he doesn’t know when Cheryl’s birthday is, but knows that Bernard doesn’t know either. From Albert’s assertion, Bernard says he does know when Cheryl’s birthday is. Knowing that Bernard knows when her birthday is, Albert says he knows also.
So how could Albert and Bernard possibly determine the date of Cheryl’s birthday knowing only this much?
Albert knew Bernard didn’t know the answer because the month wasn’t May or June. How did he know that? Each of the May and June answers contained different numbers associated with the right day, which eliminated the possibility of the answer being any of the first five choices: May 15, May 16, May 19, June 17 and June 18.
When Bernard found out that Albert knew the answer, he used the same logic to determine that the answer wasn’t any of the first five choices. Bernard also figured out that he could eliminate July 14 and August 14 from the list since they contain the same day, leaving him with the possibility of only July 16, August 15 or August 17.
Bernard then realizes that there’s no way Albert could know for sure if the correct answer was August 15 or August 17, since they are the same month.
That means the only answer left is July 16. More