Hi Bhanu, 

A 33% of passing mark is for a total out of 100. Therefore, you require to have atleast 33 marks in the said subjects, out of 100. Meaning that both theory and practical marks will be taken together and then resulting marks will be considered to see whether you have passed or not. If you have more questions about your Class XIIth Board Examination, keep reading Careers360 using the link given below: https://www.careers360.com/courses-after-12th-science

Thanks,