Is the 50% marks in hs for neet eligibility combined the summation of theory and practical of pcb individually or theory and practical taken together ?

Yash, for calculating your NEET eligibility your marks in Physics, Chemistry and Biologycare considered. So you need to pass the theory paper individually in these 3 subjects and then add up your practical marks to calculate the aggregate. For example, if your theory is for 70 marks and practical is for 30 marks, you should score the pass marks in your theory. And then you add up Theory and Practical marks. Lets say you scored 35 in Theory and 25 in Practicals. That is 60 out of 100. This is for Physics. You need to do the same for Chemistry and Biology. Now to calculate the aggregate required for NEET, you need to add the total marks of Physics, Chemistry and Biology, divide it by 300 and multiply with 100. So if you scored 60 in Physics, 50 in Chemistry and 70 in Biology, you need to calculate this way:
60+70+50/300100

You need to secure 50% minimum aggregate. It is 50% for General Category, 45% for PWD and 40% for OBC,SC,ST.