JEE Main

Yes, chances are good. I think he will get CS in fourth or fifth round of JoSAA.

You can apply for it. Chances are very less but still you should try for it. You may get a seat in last rounds.
https://www.shiksha.com/college-predictor

Hi
https://www.shiksha.com/college-predictor
Use this link to know about the colleges available to you.

Hi
https://www.shiksha.com/college-predictor
Use this link to predict your colleges.
https://www.shiksha.com/b-tech/jee-main-exam-cutoff.

Hi
NTA allows some corrections in the mistakes made while filling out the form. A window is given to students for this before the commencement of exams. However you have already appeared for the exam. You may attempt this when similar window is given to the students by NTA during April exam cycle. In the meanwhile I am attaching a link that will give you some information about this. https://www.shiksha.com/b-tech/articles/jee-main-correction-blogId-1943.

Hi
https://www.shiksha.com/b-tech/jee-main-exam-cutoff
https://www.shiksha.com/college-predictor
You can view the link above to get a list of colleges that are available to you.

According to your score, there may be chances of getting a seat in this college.

Check with the college authorities, you are looking for.

Chances are very less or I can say there is no chance. But still, you can try it. Better to improve your marks in the next upcoming JEE Mains exam.

First, let me take this opportunity to tell you one thing that your marks doesn't every time tells your true potential. Every time you do something, you get to learn some new things. This is the beginning of your new life. Now without taking much time, I would like to answer your question, IEM Kolkata is one of the best private colleges in Kolkata.To get admission to CSE in this college you need to have rank around 20k (Kindly check percentile vs rank) in JEE-MAINS.