The process took 1 day. I interviewed at Jane Street (New York, NY) in Sept 2011
Interview
Phone call that dived immediately into mental math and probability brainteasers. No fit questions.
Interview questions [1]
Question 1
You are playing a game in which four fair coins are flipped and the amount of money you receive in dollars is equal to the number of heads that appear in total. If you do not like the outcome of the first four flips, you have the option to re-flip the four coins, but you are obligated to take the second outcome. Determine a fair value fr the game.
Many rounds of brainteasers, some of which are more rapid fire in nature and others which require you to flesh out a detailed answer to a complex problem. Be well rested and well prepared!
mostly maths probability questions - a lot of conditional probability, relatively easy in the first round, but you need to think out loud - you need to be really fast
4 rounds in final. The first one is market making of cards. The rest are especially designed games. The interviewer may ask added question along the playing of the game