Hi,

To get admission in a good college from Assam, you have to give CEE exam.  The top colleges get high cut-off i.e. for Assam ENgineering College the cut-off goes as high as 130 marks. Although as you want to know your probability of admission in Dibrugarh University at a score of 90, it would be tough to take admission as according to previous year records the cutoff for the college went at 99 marks for OBC category. And the least a cut off went was 96 marks for OBC. So I would suggest you use this college predictor for Assam CEE. 

https://engineering.careers360.com/tags/college-predictor-of-assam-cee

 I wish you all the best

Thank You