There were two interviews. The first was a brainteaser, puzzles, HR and an estimation problem. They are looking at people who can think on their toes, have the presence of mind not to make silly mistakes and have good motivation to take up this post. With a decent grasp of mathematics, this interview should be a breeze. The second interview was a case study and was conducted by the partner of the firm. Communication skills, structured thought, logical reasoning, quick mathematical skills and confidence were tested thoroughly in this interview.