CAT

To leave CA for MBA is not a good option because after completing CA you may get better career options as compared to MBA. If you can manage your time you can pursue both at the same time. Yes, IMT is very good college, so, if possible you can continue both at the same time.

You must have above 90 percentile for the same.

You can follow Arihant published books and must follow previous solved papers.

Yes, you can get seat in a good college. To apply in a good B School you must have min 50 % marks in graduation. But you must have a good CAT/MAT/XAT score to make sure you get selected in a good college. Your work experience will also help you in getting into a good college. Some good colleges prefer to have students with work experience.

The chances of getting admission also depend on the GD/PI and the percentage and extra curricular achievements.
All things effect the chances of getting admission.
For fee and other details and for more information, refer brochure:-
https://www.somaiya.edu/media/pdf/PGDM_Admissions_Brochure_2017-19.pdf .
FAQs:-
https://www.somaiya.edu/media/pdf/FAQ_2017-19.pdf

Dear,
As per your desire, institute or university admission, you need to appear one of them. But, most of the students try their luck in CAT and MAT exam to get best B-School in Delhi NCR but I would suggest you to target Best B-School in India.
You can even appear for G-MAT for abroad education because there are good universities especially in management and the country you can think is Australia, Us and UK too.
All the best.

Dear Hitesh,
Please share your qualifying examinations % achieved so far. Then, any decision can be taken.

Chances for getting a call is high, you can qualify for GDPI rounds and if you prepare well enough you can convert into the final seat. You have good academics and experience which can be helpful.

Yes surely. This was the first list of short-list. Now, after a week, a second list will be released. No worries.