For entering in this prestigious college do I need to score well in my 6th subject, that is maths. Or just passing it will help?
For entering in any presitigious college, and if you belong to commerce background, then you just have to pass the mathematics as your 6th subject. Best of 4 is taken into account usually which compulsarily includes english.
Note - But there are many private colleges too which need some minimum percentage in mathematics for ccommerce courses.