I applied through college or university. The process took 2 weeks. I interviewed at Jane Street (New York, NY) in Jan 2015
Interview
Lots of quantitative questions. Some were mental and quick in nature, others were more involved and allowed for pen-and-paper.
There were three total interviews: the first was all mental math and took about 15 minutes. The second and third were longer and involved more difficult math questions. On some you were expected to estimate the answer, not to get the exact answer.
Interview questions [1]
Question 1
You have a rubiks cube and you paint the outside red before breaking it up into 27 smaller cubes. You pick one of the smaller cubes randomly and roll it. What is the probability that all of the sides facing upwards are unpainted?
I had a phone screening call from a recruiter, they asked some standard probability questions, bayes rule, and expected value about dices. Overall experience was pretty good. Make sure you prepare your probability
Interview questions [1]
Question 1
Expected value, if throwing a dice, 2 dices and 3 dices with option to reroll.
I applied online. I interviewed at Jane Street in Nov 2022
Interview
Very smooth. Around 30mins first round 1hr for the second round. First round consisted of easier probability based questions. Second round was similar but harder and longer questions. The interview process if approached in a calm composed manner should be easier to analyse
multiple phone interviews and a full-day Zoom interview. Interviews got longer and longer over time, but every person was very kind and helpful with hints when I got stuck. The questions get harder as the rounds progress and generally don't have a closed form answer in the later rounds
Interview questions [1]
Question 1
they describe the rules of a game and ask if you want to play it based on your expected earnings