Hello dear! 

If you have missed your class 11th syllabus then you have to compensate it. Almost 40% of questions are from class 11th. 

I want to suggest you to cover at least those topics which have more weightage like coordinate geometry in mathematics (about 5 questions excluding vector 3-d),chemical equilibrium and thermodynamicsin chemistry  mechanics, heat and thermodynamics in physics. As no more time left for jee. I suggest you to solve previous year question and sample papers. By solving papers and after seeing the sol. part, most of the missing concept will get clear. 

I hope you get it.