It all depends on how you are taught and the quality and motivation of the student, plus the reputation of the school. I did my own in 8 weeks way back when, and that was with negative marking
. My own feeling is that if you do well with the non-multiple choice questions at the technical interview, how well you did the real exams won't matter. Everyone knows that most people have to crash the databases anyway - you cannot pass the current exams on knowledge alone.
phil