I’m not sure what’s crazier to me: asking someone to demonstrate a live proficiency of an abstract skill that is only tangentially related to that actual day-to-day activities of a role or just assuming that because someone has some high credential that they would be good in a given role.

DE Shaw is a financial company filled with maths guys, doing statistical analysis and modeling all day. A math puzzle is the most normal question you could be asked there.

The real question is why Larry Summers is going to a quant interview? Did he apply for a quant role?

They hired him as a managing director.

For many roles at a hedge fund, being able to do mathematics quickly and intuitively is a valuable skill. Not sure why an economist applying for an MD job would need to be tested on that, though.

He should have called their bluff and failed the quiz on purpose. What are they going to do?