Dear Aspirant,

Generally in any college providing B.Tech course you have to maintain your 75% attendance during the whole year. It is mandatory in most of the colleges.

Now excluding the sundays and national holidays , a minimum of 250+ days you must be present in the class. This is just an estimated data.

Now to check holidays for a your college you can check its academic calender on its official website. So by subtracting all the holidays from 365 days , you can calculate the 75% of remaining days. By this you will get a general idea for days to attend classes in your college.

Hope this helps.