Government & Defence Entrance Exam

It depends on your interest and what are your preferences.
At first, you ask yourself that you want to go for civil services (government job) or business and management is your passion. What makes you feel good?
Both are very reputed sectors and you have many responsibilities. Both offer you attractive salary and various perks.
However, our society gives preferences to the government jobs. But after going to IIM, your life will be no more different.
check out all the pros n cons of both the options and decide according to your condition and interest.
All the best for your future ahead.

If you want to appear for the above mentioned exam, you can fill online application forms at the official websites.
Keep visiting official websites for the latest recruitment notifications:

ISRO Exam 2017 Eligibility
BE/B.Tech or equivalent qualification in first class with an aggregate minimum of 65% marks or CGPA 6.84/10 (average of all semesters for which results are available). Minimum of 65% marks or CGPA 6.84 in section B alone for candidates with AMIE/graduation IETE qualification.
Candidates who are going to complete the above course in the academic year 2016-17 are also eligible to apply provided final Degree is available by 31/8/2017. The qualification prescribed and the benchmark are only the MINIMUM requirement and fulfilling the same does not automatically make candidates eligible for Written Test.

For applying for UPSC, you must have completed your graduation from a recognised University. And, the minimum age required is 21 and for general category, the age limit is 32. Apart from this, there is no criteria of minimum percentage or something.