I want to prepare for BITSAT and i m very much intrested in it... its already end of the january and i will be studying for boards now.. so my question is, how should i prepare for BITSAT in around 40-45 days after jee mains?

@ HIMANSH 
in bitsat the thing is they are asking tricky ques but not long ques like jee does..
so, arihant bitsat test series book will help u a lot for that,,
even u can go through the previous year papers of bitsat which are there in askiitian websites..
and also the study material that askiitian is providing, go through that, clear your concept..
do some sample paper and solve mock test paper.. as u have less time in ur hand, so utilise that time efficiently..
now,when u are preparing fr boards then make sure that 12^th portion of bitsat level also get covered within this time, 
so, when board exam ends, u can start practicing the 11^th portion properly..
ALL THE BEST...

It's simple go throw previous question papers 10 days after that prepare 8th class to 12th  class maths, physics, and biology well