hello aspirant

i am here to answer your question.

to apply for NDA exam you should be 12th Class pass of the 10+2 pattern of School Education or equivalent examination conducted by a State Education Board or a University and minimum age limit should be 15.7 years (not later than 1st January 2005)/ 16 years during the commencement of course. now to answere your question you have to score 25% in each and every subject. you cannot qualify the exam by gaining 25% of overall marks.

i hope my answere will help you.