Hi,

To ensure the admission in BHU you have to attempt at least 70 - 75 correct question. The no. of question may vary as the difficulty level of examination. Generally cutoff is 205-210 for general and obc category. For SC and ST  it is very low, for a good combination if you secure as general and obc 220–240 marks then you will get your desired combination as well as hostel too.

For the general students cutoff is really high, you require anything above 200 for a good combination and an Honors of your choice along with the hostel.
I can’t give an accurate prediction but above 195 is better if you wanna be in safe side, it depends on the performace of other candidates in the exam. But going through the trends I would say above 270 out 0f 450 shall be a safer score to get admission in BHU B.Sc Maths.

Hope this helps.

All the best.