Over six years now since I did the tech exam but...
Out of seven of us being interviewed on the day, six ended up in the company. We all pooled our knowledge during the exam (it was not being monitored) so ended up with identical answers.... except one chap who clearly had a greater level of knowledge and did his own thing. He may have achieved a higher exam mark but I know he does not work at Virgin.
Just possible that the exam is a cover to find out who the team players are?
Good luck with the selection process