Multiple rounds of phone interviews consist of mostly probability and game theory(strategy) problems. Onsite final interview after 3/4 rounds of phone interview. Each interview is between 30 to 60 minutes long.
Interview questions [1]
Question 1
actions in a game. The die starts with upface
1. The two options you can perform are to roll and to take. Performing a roll re-rolls the current upface of the die. Performing a take allows you to cash out the current upface of the die. Note that the game does not end when you perform a take and that you do not have to roll between takes. Therefore, for example, you can just perform 100 takes on the initial $1 upface and walk away with $100 guaranteed. Your strategy is to cash out the upface when you roll at least some threshold n for the first time. You fix this n at the beginning of the game. Assuming rational strategy in selecting n, what is your expected payout on this game?
1st round--45 minute phone call purely technical with brainteasers. no behavorial besides brief introduction of self. i believe there are 2nd and 3rd round phone and a final superday but didn't make it past there.
multiple online interviews, technical in nature, followed by an in person in office interview which lasted an entire day and had multiple stations. focused on problem solving, probablity, game theory etc etc
I applied online. The process took 1 week. I interviewed at Jane Street (London, England) in Nov 2025
Interview
They started with a basic introductory question followed by some probability based stuff. Wasn’t too difficult but you have to ace it, they expect perfection. They cut the interview off at exactly 30 minutes, and will provide hints if you need it though it’s not a good sign if you need them.
Interview questions [1]
Question 1
You have 20 cards. 1 is black the rest are red. You keep drawing cards and get $1 for each red, but if you draw the black the game ends and you get nothing. How do you play and what’s the average payout? Now drawing the black card makes your score go negative, but you can continue drawing cards. What’s the strategy and expected payout now?