Institute like ISB Hyderabad does not have a management quota. Admission at this institute is strictly merit-based. They choose students based on their academic record, problem-solving skills, and good attitude. Even if you have a good academic record you still need to do well in the interview, in order to get a seat.
Eligibility Criteria-
ISB looks for students with a balanced profile, and your school and graduation scores will be considered. They should be above average. Only then you'd be called for the interview. You should focus on highlighting your skill and value in your essays because scores will do only so much.