2 rounds of interviews are centered on questions that appears in many other quantitative interviews, like probability, statistics, financial applications. It would be nice to really work on these commonly asked questions, so that you can work out quickly. I was not quick in getting the answers out, which may caused the interview. But I really did not work on these problems ahead of time, so, I do not regret. On the other hand, does really mean anything at all, to get these answers quickly? I do not know. Typical interview at Goldman sachs will take 5 rounds of phone interview, grueling for many people, including me. You have to wonder whether the interviewer also get tired of this. Think about 5 interviews per week, when they are hiring, each about 1 hour long, that is, you are spending 5 hours on this. Take it to 3 weeks, only interviewed 15 people, already 15 hours of your life gone. what a waste. Anyway, I would like to say, this whole process is a bit sick.