hey kunal

for calculaton of best of fours 30% practical and 70% theory marks is considered . now if you have got marks out of 75 then calculate the effective percentile of each subject and note down your percentile by taking 75 as total like if you have got 60 marks then your percentage is 80% ,however go to the official du portal

i think this link will be helpful for you

http://du.ac.in/adm2019/pdf/BulletinForUpload30May2019.pdf