Chandan Kumar , I would like to tell you that you have asked a great question. Many students think that jee mains is a very tough exam but the syllabus is quite in range as it is same as of class 11th and 12th .You may not be able to get 150 - 180 marka only on the base of class 12th syllabus but if you go for 11th and 12th both then it is achieveable.