It depends but the thing is that na how deeply you want to cover the syallabus and how many times you have already revised in previously.
So for an amateur it can take 8-9hours ,sometimes 10-12hours too n if you are a pro having experience of 2 years or more then you can cover it within 2 hours excluding pyq's practice and the later one is imp onee.
Summery-depends on person to person.
Thank you
