Jay, for starters, your 12th marks only bear importance in you being eligible for NEET which is the entrance examination for admission to Medical Colleges across India including Gujarat. Now if you are enquiring about the 12th marks required for being eligible to appear for NEET, then it is 50% aggregate in Physics, Chemistry and Biology. It is 50% for General Category, 45% for PWD and 40% for OBC,SC,ST. Now the distribution of marks between theory and practicals is not 50-50. You should clear the subject in theory and secure the minimum aggregate. Lets say if the theory is for 70 marks and the pass mark is 18, you should secure atleast 18 marks and then secure remaining marks in practical. The concept is that you should pass in the subject and score the aggregate.