IITians are at a massive advantage in CAT

So I have been preparing for cat for a month and get around 60s in mocks. My brother who went to IIT looked at the syllabus and said this exam looks so easy, he can get 90%ile without even studying, I thought he was bluffing and underestimating the exam, I said him to attempt the CAT 2024 slot 3 paper mock, the thing is he scored 70(23/24/23) which is like 95-96%ile without even studying in a single minute for this exam, meanwhile he was sitting in the hall where all of my family members were watching reels and playing music, this was insane to me, he wasn't even aware there was a calculator in exam.