I have scored 74 in 10th std, 82 in 12th std, 64 in UG, what are my chances with the IIMs, especially A, B, C?
This video, in a tribute to Hitchhiker's guide to the galaxy more or less says the answer to this question is 42. As the video says, only certainties in life are death and taxes.
To elaborate on this, I am going to start with a quote from Donald Rumsfeld for this one "There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don't know. But there are also unknown unknowns. There are things we don't know we don't know".
Now, why have I written all this? This question, and its sister-questions, cousin-variants, nephews-nieces etc can all be categorized under "No need to know unknowns".
Suppose I were to tell you that to get a call from IIM B, C and L you will need to have 99.68, 99.71 and 99.23 with your profile, how exactly will it influence your CAT preparation? Further let us say, you have attempted 82 questions in the paper with 10 minutes to go. You know that with this attempt number, you should be able to get 99.73. Will you stop right there and say, "I can take rest now. I dont need any more marks."
I took my first CAT (relevant one) in 2000. Back then, the exam was paper-based. There were no percentile scores, no section updates, no new IIMs. We guys took CAT in December. By about February, IIM A, B, C, L would post their interview invites by snail mail (no email either). So, if you did not receive that post, you can assume you just missed out. So, you had to keep the postman in good spirits. There are endless stories of guys nearly missing out on interviews because the post got mixed up.
Now, thanks to this surfeit of information available, there is this enormous temptation to analyze everything and try to get some 'certainty'. Whether this question gets 100 replies or 1000 replies, whether 'experts' chip in or experienced candidates share their 'wisdom', you are no more likely to know an exact target or a surefire solution than you were before.
So, forget about this, put your head down and prepare for the exam. There is one thing that you can be sure of. Ceteris Paribus, a higher CAT score will give a candidate a higher chance of getting any admit.
As far as your question is concerned, for IIM A, B, C you need 99.6+, for IIM ILK you probably have a shot with 98.5+ (with L requiring more). 96+ should give you a shot with the new IIMs. If you are thinking, why couldn't this guy have given this last paragraph without going on a rant. Where is the joy in that?
Note: I had written the above as an answer to a query on Quora. Since Quora does not protect writers' freedom, I have pulled down the answer from Quora and published it on the blog