Ugh, Cheryl. Everyone hates you right now. Whenever we find out when your birthday is, you’re not even getting any presents.
The question isn’t as simple as it seems. It was first posted by Kenneth Kong on his Facebook page, who is television host in Singapore. It’s intended for sophomores and juniors participating in the Singapore and Asian Schools Math Olympiads, an annual brainiac competition.
There’s actually an answer. Chang admits that the logic puzzle is “particularly convoluted” and it helps to write it out in a table. His dissection is long is so we’ll leave you to it.