hi ansari naeem 

i hope you are talking about bachelors of computer science . in most of the colleges which conducts entrance exam the eligibility criteria is about 55% aggregate marks in your 12ths . however some may ask for 60% but such colleges are very few . and the colleges which takes admissions on the basis of merit ,then you have to score over 90% in your boards ,however if you want it safely then try to score 95+(which is the cutoff of the du's top colleges )