CUET

For getting admission in mathematics hons the scores of physics, chemistry and mathematics are evaluated. Only these three are considered for admission and your score should be around 350. 

According to the previous year cutoffs, you will surely get admission.

If you want only BHU then you can give the CUET exam again next time. Because on this score I don't think you will get a seat in BHU even in affiliated colleges. But if you are from sc/st/ph category then there may be a chance. You can register for counseling and see what happens.

No, CUET UG is not compulsory to get admission into the BSc course at Dr. D.Y. Patil ACS College. The eligibility criteria to get enrolled in the BSc course are completing higher senior secondary with a minimum aggregate of 50% (45% for the reserved category), and the admission is merit-based. However, for some of the offered BSc specialisations the admission will be granted as per the college's selection process and university guidelines. Thus, for those specialsiations, candidates are required to contact the college's admission department directly.