The internet is getting pretty mad at Cheryl. She just made friends with Albert and Bernard and they want to know when her birthday is (Why? Maybe they like baking birthday cakes. Maybe they're budding astrologers. Who knows?)
Instead of telling them (because that would be too easy), she gives them a puzzle to solve. This puzzle was then given to students in the Singapore and Asian Schools Math Olympiad (SASMO) and it is instead stumping adults around the world.
The Olympiad (of which this is one of the most difficult questions) targets the top 40% of high school students, making them stretch the limits of their logic. So, can you solve it?
(No spoilers at the link, though I can't vouch for the comment section)