JEE Main

To pursue B.Tech in CSE in DTU, you rank should be between 1000 and 3000.

Anything above 220-230 would be good enough.

Hi,
If you secure 68% marks in your boards, then you are not eligible to appear for JEE mains. Since, you must get at least 75% in your board exam. But, why are you not aiming for 75% or more and aiming for only 68% in your board exam? Top colleges rely on ranking in JEE and hence if you want to get admission in top ranked institutes, you must aim to get more than 75% in your boards.
Best wishes.

Yes, you are eligible for JEE mains, but not for JEE advance.

If you have 55% in class 12th, then you are eligible, but if you want NIT or to qualify for IIT, you have to score at least 75% in class 12th.

Hello,
Almost all of these entrance exams are conducted with aim of testing student's ability of logical thinking and knowledge of fundamentals of science. I would therefore advise you to stick to brushing up your basics. Besides, you will have to learn to answer in stipulated time. There are practice papers available, you can try these. But, get answers vetted by your professors.
Best of luck.

Yes, if have science stream with PCM.

No, to clear its cutoff you have to score more than or at least 75% in class 12th.

You can also give the exam when you are appearing in 12th. It is not compulsory to clear before JEE exams. But, after JEE, when you want to take admission then JEE marks and your 12th percentage will be seen.

Physics, chemistry, and maths are required for the joint entrance examination.