Joffy - I pulled those figures and that example out of thin air. It has been a year since my assessment so my memory of it is not too clear. However, there is a much simpler way to do that than simultaneous equations.
Google Speed, Distance, Time questions and practice those as this is the kind of thing you need to be able to do. Granted the real questions will no doubt be doctored to give rounder answers than mine but it can be worked out in 30 secs or less with pen and paper.