If A leaves Melbourne travelling to Sydney at 90 km/h then, after hours, A will have travelled km along the route.
If B leaves Sydney at the same time as A leaves Melbourne, and B is travelling to Melbourne at 100 km/h along the same route as A is travelling to Sydney, then, after hours, B will have travelled km along the route.
Since A and B are travelling along the same route and left their respective starting points at the same time, they will meet when their collective distance travelled equals 950 km, the length of the route. That is:
So, A and B meet after each travelling for 5 hours. At this time, A has travelled and B has travelled .
So, A and B meet at the point on the route that is 500 km from Sydney a d 450 km from Melbourne.