It really actually wasn't that simple.
The program was not open to public until 2000, just relatives or great friends of the iconic ones who were invited to apply.
I don't think it is any great secret that plenty of Sons of captains & senior managers went into a building in Coward Street that is opposite a Hotel after hours for a little practice of the said test. Heard a lot of them needed five full runs through it till they finally got the pass grades.
Qantas Pilots - the best of the best.