The above poster's advice isn't technically true. When I sat the performance exam, the graphs supplied in the examination booklet were so worn, there was a hole in the page where the correct answer should have been read off. Unfortunately, the hole encompassed several of the multiple choice answers, limiting how educated a guess I could make given that the necessary section of graph was missing.
You may also "fail" a few exams depending on your ancestry, regardless of performance.
I sat them a decade ago though, so i hope things have changed!