Answer:
Brenda have travelled for 6 hours before Scott caught up with her and she have covered 204 km.
Step-by-step explanation:
Given;
Brenda's speed = 34 km/h
Scott's speed = 51 km/h
Scott's time of travel = 4 hours
The distance covered by Scott is;

Since Scott have caught up with Brenda after 4 hours, the distance Brenda have travelled before Scott caught up with her is equal to the distance Scott travelled.

Brenda's time of travel is;

Therefore, Brenda have travelled for 6 hours before Scott caught up with her and she have covered 204 km.