'Passmark' is 112 - but as VP says higher scores are more competitive - to my understanding though, as long as you pass you are in with as much chance as anyone else providing you pass the other elements of OASC.
However, if by the end of the process Mr A and Mr B have produced equally weighted write ups, and are deserving of passing the selection process, then aptitude can be used as the tiebreaking score to determine which of the two are selected.