It is possible but chances are less. JEE is one of the toughest exams and have a lot of competition. By solving previous year papers and deep understanding of concepts you can crack the exam but scoring 200 requires practice. Understanding the concepts is very important but working with different types of questions is equally important if you want to score really good marks. But as you are saying that you are able to solve question then I think you can do it.

There are no shortcuts to success.

And I don't think you are running out of time. If your are not starting from scratch and you start preparing now then also you will have enough time.