Hi Student ,

No, it is no compulsory to have a BA degree to pursue a masters . In most of the institutes the eligibility criteria for a masters in  is around 45-50% marks in your undergraduate degree in any field. But in a few reputed institutes UG is compulsory.

10+2+3 means class X, class XII and 3 years of graduation .And 50% aggregate means 50% average of your first year, second year and third year of 3 year bachelor degree course.
A few colleges ask for 60% consistent score in all the three levels as minimum eligibility criteria for post graduate courses.

Thank you