Hello Dear,

Delhi University takes the admission of maximum of the BSc Mathematics courses via merit list on your class 12th marks. You need to have high percentage in 12th to get into University of Delhi. Usually the first cutoff gets higher than 95%. They consider three subjects for the admission and to calculate the percentage. For previous years paper you can follow the link:

http://web.du.ac.in/PreviousQuestionPapers/UNDER%20GRADUATE/

Hope this was helpful