Goodluck! Having some information about the company he's being interviewed by helps a lot, and also sometimes they might ask some technical qns related to his field of study, but I think that might be the second stage. Don't panic! getting the right answer is not a big deal, they usually look for the method that you approach to solve the problem if you can't get the right answer (I guess that is just to check how you'd approach problems if you were hired). Plus, something else that leaves a good mark is you know how at the end they ask you "Okay so we're done here do you have any qns for me at this point?" Asking question about pay is a HUGE NO NO, but it leaves a really good impression on them if you ask something related to your position, just to show that you're really interested in this job. Nothing too complicated, may be something simple like "If I was to be hired what would be my first project be like?" Goodluck! I'm sorry if you dont find this helpful.