Answer:
Trawler B should set off on a course of 120°.
Trawler A is traveling at 20km/h on a bearing of 60°. This means that Trawler A is traveling north-east. Trawler B is traveling at 25km/h. In order to intercept Trawler A, Trawler B must travel on a bearing of 120°. This means that Trawler B must travel south-east.
The two trawlers will eventually meet at a point that is 40km east of Trawler A's starting position and 20km north of Trawler B's starting position.