The question appeared earlier this month during the Singapore and Asian Schools Math Olympiad.
ABC News’ Gio Benitez takes a look at the tricky problem, and solves the puzzle in a step-by-step video guide shown above.
The problem lays out a scenario in which Cheryl meets two new friends, Albert and Bernard. They want to know when her birthday is, so she gives them 10 options, and each boy gets one hint.
Sec 3, meaning Secondary 3, refers to its being made for high school students.
But some were worried the problem was for even younger students, specifically kids around 10 and 11. The Singapore and Asian Schools Math Olympiad issued a statement on its Facebook page, addressing the concern.
“We think it is important to clarify so that Singapore parents will not start to worry so much... [this] is actually a question from the Secondary 3 and from the Secondary 4 SASMO (Singapore and Asian Schools Math Olympiad) contests,” the statement said.
It continued, "This is a difficult question meant to sift out the better students.”