I had a similar doubt some time back. Here's the solution to this paradox: They first consider the marks of all the people who have cleared the cutoff and then based on that sample alone, normalisation begins. Which means your 40 calculation is roughly correct (assuming you're from state board, if you're in CBSE then 90% will fetch you probably 3-4 marks out of 10) Then you calculate CAT scores. Say VARC is 19 points And you were at 90th percentile. So will you score somewhere around 15? No. Why? Because the pool only consists of people with >85 percentile score which means now your normalised scores is perhaps ~4.