MCA

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https://www.shiksha.com/b-tech/upsee-exam-question-papers

You need to have good academic scores (at least 70%), good IELTS score, SOP (Statement of Purpose), LORs (Letter of recommendation).

All colleges have slightly different eligibility criteria viz,. For admission to students applying for MCA after B.Com. The important ones being:-
1. The overall percentage requirement in graduation ranges from 50% to 60%
2. Some college insist on similar percentage range in their XII (12th / Inter) exams.
3. Colleges also insist that students have Mathematics as a subject either in graduation or have passed XII with Mathematics. Students needs to check with the colleges they are applying on what exactly is the eligibility criteria of that particular college.

Some top colleges are:
1. Department of Computer Science, Savitribai Phule Pune University, Pune
2. School of Computer and Systems Sciences, Jawaharlal Nehru University, Delhi
3. School of Computer and Information Sciences, University Of Hyderabad, Hyderabad
4. Birla Institute of Technology, Mesra
5. Motilal Nehru National Institute of Technology, Ahmedabad.

It is compulsory in good colleges and in some colleges, they accept admission even if you have not taken maths in 12 std.

The only drawback of BCA+MCA over B.Tech is that you will have to spend 1 extra year in BCA+MCA but I would suggest you to go for BCA+MCA because it makes your fundamentals strong if you are not from computers background. Also, there is less unnecessary pressure and workload in BCA so that you can focus on your skills better. As far as salary is concerned, to an exceptionally skilled person there is no limit. But even if you are sound at coding and have some good logic then your minimum salary will start from 25k to 30k and with your skills, your salary will increase exponentially.

Our world revolves around technology today, which is because of computer. BCA & MCA is definitely a good choice, if you excel in it. Sometimes, college doesn't matter, what matters is your performance. Good performers are always appreciated and reach good heights. Do not keep your eyes salary, if you happen to be a good candidate, you ll earn well. Just work on gaining excellence.

In technical round, they ask the questions from your previous course like data structure questions, programming etc.
Good luck.