If you thought those Singaporean maths exam questions were infuriating, you're not going to enjoy this one.
Professor Dylan Selterman at the University of Maryland offered one of his classes the chance to get extra credit at the end of an online exam paper on social psychology - but it came with a rather meta caveat.
The extra question read:
Select whether you want 2 points or 6 points added onto your final paper grade. But there's a small catch: if more than 10% of the class selects 6 points, then no one gets any points.
One of Selterman's bewildered students posted a picture of the question on Twitter where it was retweeted thousands of times.
The tweet has caused something of an existential crisis online as people weighed in on the moral implications of winning six points for yourself at the expense of two points for everyone.
Selterman told ABC News that he sets a real life "tragedy of the commons" question for students every year, which tests whether individuals will behave according to their own self-interest at the expense of the interests of a group by depleting some common resource.
So far, only one class has been selfless enough to get it right.
In reality, if too many people overuse a common resource then everyone in the group suffers, not just the selfish ones... This is what I want students to learn from the exercise. Their actions affect others, and vice versa.