Jane Street Capital
www.janestcapital.com New York, NY 150 to 499 Employees
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# Jane Street Capital Trader Interview Questions & Reviews

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### Interview Experience 46 Ratings

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54 interview experiences
Updated May 13, 2013
in
Interview Outcome:   All No Offer Received Offer

## Trader at Jane Street Capital

No Offer – Reviewed May 13, 2013 New

Interview Details – Applied through school and got an interview within a week.

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## Trader at Jane Street Capital

No Offer – Reviewed Feb 10, 2013

Interview Details – Probability questions
15000*500
.02 of that

4 coins, I flip them, give you dollar for each heads. How would you pay to play?
What if I give you the option to reflip any coin?
What if I make you reflip?

Interview Question – 4 coins, I flip them, give you dollar for each heads. How would you pay to play?
What if I give you the option to reflip any coin?
What if I make you reflip?

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## Trader at Jane Street Capital

No Offer – Interviewed in New York, NY Nov 2012 – Reviewed Dec 8, 2012

Interview Details – I got through four phone interviews before I was taken out of the running. One thing that was annoying was that interviewers would constantly cancel on me, but HR was very good about rescheduling them. Interviews consist of a TON of mental math and brain teaser questions. You really have to be on top of your game for every interview.

Interview Question – We are playing a game where we start at 0 and flip a coin until someone wins. Every heads that is flipped adds +1 to the number and every tails add -1. If the number reaches -10 I (the interviewer) wins and if it reaches 20 then you win. What is the probability I will win?

I am thinking of a 10 digit number. The first digit is the number of 0s in the number, the 2nd is the number of 1s etc...What is the number?

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## Trader at Jane Street Capital

No Offer – Interviewed in New York, NY Feb 2011 – Reviewed May 2, 2012

Interview Details – I was contacted by the recruiter the next day after my application. The recruiter asked for some sample code from some recent projects. After I submitted the code for a couple of projects I had worked on, I was contacted for the first (phone)) interview. The response were very fast. My interviewer was very polite and seemed very smart.

Interview Question – What is the sum of the digits of all the numbers from 1 to 1000000? This is different from the sum of the numbers. For instance the sum of the numbers from 1 to 10 is 55 whereas the sum of the digits is 46.   View Answers (12)

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## Trader at Jane Street Capital

No Offer – Interviewed in New York, NY Feb 2012 – Reviewed Mar 6, 2012

Interview Details – Mental math and probability questions

Interview Questions

• how many commercial aircrafts are sold every year in the US   Answer Question
• A has 5 fair coins and B has 4 fair coins. A wins only if he flips more heads than B does. Probability of A winning?   View Answers (6)
• 5 pumpkins, given the sum of weights of every pair of two pumpkin, what's the weight of each pumpkin?   View Answers (2)
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## Trader at Jane Street Capital

No Offer – Interviewed in New York, NY Dec 2011 – Reviewed Dec 15, 2011

Interview Details – Interviewer was very friendly. Helped me work through problems I was stuck on. Told me I could take as much time as I needed to answer the questions. Cannot use pen and paper. Interview consisted of four mental math questions and then some probability questions. Afterwards I was allotted some time to ask questions about the firm.

Interview Questions

• Let's play a game - I give you a 12 sided die and will pay you whatever the die lands on. If you are unhappy with the roll, you can choose to roll another two 6-sided dice and I wil pay you the sum of the two dice. How much are you willing to pay to play this game.   View Answers (10)
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## Trader at Jane Street Capital

No Offer – Interviewed in New York, NY Aug 2011 – Reviewed Nov 3, 2011

Interview Details – There were 3 phone interviews. No questions about self or goals or anything like that. All the questions were involving math or problem solving. The first interview was a few mental math questions followed by 4-5 relatively simple brain teasers. The next two interviews both only consisted of 2 brain teasers and a confidence interval question that you have to explain.

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## Trader at Jane Street Capital

No Offer – Interviewed in New York, NY Sep 2011 – Reviewed Oct 5, 2011

Interview Details – Very interesting interview experience. The trader I talked to was also a graduate of my university, and very laid-back. Very strong and loyal culture, but it sounds like an extremely intense environment. The interview consisted of like 5 minutes "fit," but it wasn't forced at all, mostly conversation. The rest of the interview was straight-up quantitative brainteasers and probability. Took me forever to multiple 27 times 37.. be prepared with your mental math for sure.

Interview Question – Apples cost 27 cents. How many apples can you purchase with \$10? (And do this in under 1 minutes).   View Answers (5)

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## Trader at Jane Street Capital

No Offer – Interviewed in New York, NY Feb 2010 – Reviewed Sep 4, 2011

Interview Details – It's all been said before. Started with 3 phone interviews, first was a lot of mental math, then mostly probability questions, with a bunch of different math brain teasers thrown in. The first one is easy (seemed to be mostly to weed out people who look good on paper but can't back it up), but they get harder. Completely doable--make sure to brush up on your mental math, and be ready to think out loud.

The day-long interview on site was much harder, mostly due to nerves, but also because of the length of the interview. They don't care about your social graces, just play to win. You will need to be able to approximate your confidence in your answers and wager accordingly. Admittedly, I had an off-day and looked like a fool. I have nothing but respect for the firm though, they were actually exceptionally professional (yes, their dress code is non-existent, but they have their reasons).

Interview Question – Suppose you have n points on a circle distributed such that after connecting all of the points with chords, the number of regions in the circle is maximized. How many regions are there?   View Answers (7)

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## Trader at Jane Street Capital

No Offer – Interviewed in New York, NY Jan 2011 – Reviewed Feb 2, 2011

Interview Details – The interviewer was cordial, but the interview questions were very technical. The first round interview consisted of mental mathematics -- pen and paper were not allowed. I could tell that the interviewer was not happy with my performance (never having trained for mental maths) and I was not invited back for a second round of interviews.

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