Candidates we have completed there 12th with subjects like physics chemistry and mathematics are eligible to write JEE mains. Those who qualified JEE mains are eligible to write JEE advanced.

Both the exams are pretty difficult. But nothing is impossible. If you work hard and contribute all your time towards studying you can definitely crack both the exams. But you must definitely work harder.

First step is you must be thorogh with NCERT textbook. You have to solve lots of problems in order to get speed while writing exam. Try to attend mock test as many as possible and also try to solve previous year question papers. I won't say that it is impossible but it is difficult to crack in 1.5 month. But it totally depends on your calibar.

All the best.