Hi Ventak,

You have low chances of admission by stream 2. You would have better chances of admission if you got a decent score in JEE Mains.

The admission is based on two ways:
Stream 1: JEE main marks + board exam marks (70% seats)(0.75*boards + 0.25*JEE mains)
Stream 2: only board exam marks (30% seats)
There is no specific cut off to get a seat in SASTRA University. It depends on the student who scores the highest marks. If you have appeared for JEE Mains then apply under stream 1. If your board exam marks are 90-95% and JEE main marks are between 50-120 then you can get admission under stream 1. 
For stream 2, your board exam marks should be at least above 85-90% to get a seat and if it is more than 95% you can get a good course. 

Hope it was useful to you and your query was resolved.

Feel free to contact us for any queries.

All the best :)