Dear Soni, for Bachelor's degree in Aerospace Engineering you should have passed 10+2 examination from CBSE or any other equivalent examination board with Physics, Chemistry and Mathematics as core subjects. You should also fulfil minimum qualifying marks in aggregate of the subjects. And this aggregate varies from University to University. After your 10+2 and your Bachelor's, there is no defined score that you need to achieve to get a better job. With recruiters as big as Air India, Boeing Inc, Emirates and ISRO, you can only imagine the expectations they have out of a candidate to be hired for their companies. So anything less than 80-90%, you will have to face a tough competition from your classmates, students who passed earlier than you and also candidates who are experienced than you and also have a PG to boast about. Aerospace engineering is all about designing aircrafts and space crafts. For that you need to be a brain expert. And any mediocre performance doesn't justify the nature of your job and a good placement needs a good accademic score.