BSEB

Hello
Sorry!, but there is no chance to even sit in the exams with this much score (the candidates should have obtained a minimum of 75% aggregate marks for general or be in the top 20 percentile of their respective boards. For SC/ST category, a minimum of 65% marks required).

Mathematics can be the good option. Because Maths is compulsory for pursuing Computer Science and application courses.

You have not write about the category and sub category you belongs. However if you belongs to general category and VJ subcategory and domicile of Maharashtra than you can get the B.E. Computer Engineering in asked college.

Yes you can take. The eligibility criteria is given below.
1. Applicants must have passed their Intermediate standard from the recognized board with the minimum score up of 50% in Physics, Chemistry, mathematics and English.
2. Candidates appearing in qualifying exam are also eligible to apply for AMUEEE 2020.
3. Candidate who have cleared diploma in engineering programs from AMU with the minimum of 50% are also eligible to apply for this entrance.

You can apply for DU but there are very less chances to get a good college.

You can check it by clicking here :------
https://www.shiksha.com/college-predictor

Yes, you can get admission in DU with these percentage in class 12th. In DU, your top four subjects of class 12th are considered. You will be able to get the college in 2nd and 4th cutoff list.