First of all, not all participants are eligible to write the test. The Baja committee asks for your semester marks and other details before the event and based on that publishes the list of participants that are eligible to write the exam. So from a team approx 5-8 members are eligible.that makes a total of around 120*8~1000 students.
Now there are 3 tests. First aptitude next technical followed by psychometric test.After all these, final 300 students are selected which are eligible to take part in GD/PI depending on how the company wants it to be.
Again comes the twist. Out of some 8-9 companies that comes for placement you have to choose only 3 and give them as 1st, 2nd and 3rd preference.Now the company that you have given as 3rd preference may not call you for PI/GD coz you’ve given them 3rd. Same maybe the case with your 2nd preferred company. And if due to some reason you got rejected from your 1st preferred company, the game’s over.