Good question... See you need 15 out of the 30 questions correct in each section right? It's not a very difficult job. You can score around 180 and above by using this trick. But you need to be super confident in the chapters you do. I'll give you the trick.

For physical chemistry, don't go very deep into the concepts, just do basic numericals and basic theory.. Because let's assume 10 qsns are from physical chemistry, then 5-8 will be straight forward and too easy. So don't leave any chapter but do them all upar-upar se ache khase way me.. Organic chemistry me goo deepest...tricky questions are asked especially from this section. So go deep here. Practice well.. You'll be able to solve 5-8 qsns again out of the 10. For inorganic chemistry, it's upto you,,since most things are theory only, luck matters here.. I'll tell you do coordination compounds and all the blocks periodic table redox reaction this chapter achese...

For physics and mathematics it's upto you.. Do some chapters with extra solving and extra confidence keep then in A grade. Do some chapters with a single mcq book solving keep them in B grade. And to the rest chapters that you find difficult leave them, or do them thoda thoda.. Keep then in C grade. And accordingly you'll be able to attempt 50% of the paper of the two subjects.

Study smartly brother. Best wishes. Thank you.