Kolkata

The complete 5-year curriculum costs INR 424,950 for general/OBC/KM/EWS students (caution money not included).
The tuition is INR 12,950 for the first year and INR 69,550 for the following 4 years (excluding caution money) for students who are SC/ST/PD. Additionally, the student must pay a refundable caution fee of INR 2,000, which will be returned to them once the programme is through. Hostel costs must be paid separately and at the time of registration for each semester.

Yes, B.S in Mathematical Sciences + MS in Mathematical Sciences is offered by IISER, Kolkata.

Heritage Institute of Technology is a good option. HIT offers a B.Tech. in Computer Science that is accredited by the National Board of Accreditation (NBA). The course curriculum is designed to provide students with a strong foundation in computer Science and engineering.

The best engineering colleges in Kolkata include – 

• University of Engineering & Management
• RCC Institute of Information Technology
• JIS College of Engineering
• Camellia Institute Of Technology
• Calcutta Institute of Engineering and Management 
  
  

The best MBA institutes in Kolkata are –

• Institute of Engineering and Management
• Bhartiya Vidya Bhavan Institute of Management Science
• Amity University
• Techno India University
• Brainware University       

You may choose any of the above institutes to pursue MBA. They offer best in the class education facilities for the students. 

The candidates must have passed their 10+2 in science stream from a recognized board. The minimum aggregate marks required for admission to the BS-MS in Biological Sciences course at IISER Kolkata is 60% for GEN/OBC and OBC-NCL categories and 55% for SC/ST.

Students with a B.Sc./B.E./B.Tech. or an equivalent degree from any recognized University/Institute/College in the branch of study as one of the honours/major subjects can apply for the MS in Biological Science course.

The BS-MS in Biological Sciences is a five-year dual degree programme with numerous advantages. Students pursue both undergraduate and graduate coursework concurrently, saving one year of tuition. The BS-MS in Biological Sciences is a combined programme that allows high-achieving students to earn both degrees in less time. 

The fee structure for MS in Space Physics at Indian Institute of Science Education and Research Kolkata (IISER Kolkata) is INR 1,46,000 for the entire course, the course is a two-year full-time postgraduate degree program. Admissions are based on the evaluation of the applications, some candidates will be short-listed and called for interview.

It should be determined by your category. If you are general, you must score between 80 and 110 to be admitted to the top IISERs. If you are OBC, you must score between 60 and 80, and if you are SC, ST, you must score over 40. These grades may change from year to year, but they will fall within the range that I have stated because there are basic questions on the paper, it will be easier for you to score if your basics are clear. Don't take on too much stress and be ready for it. Best wishes.