Hello Bablu

Every other person has a different brain which works in different frequencies.

What I can study in 10 hours, maybe you can study in 2.

So this is really irrelevant.

But still to answer your question, according to some statistics, a good amount of 4–5 hours a day can help you get into a tier 1 college, but those hours should be with complete dedication and for 5-6 months.