1) Take into account that the distance traveled by both car and truck is the same to their displacements (this is because the car and the truck only made one trajectory to the south).
The speed is the quotient between distance and time, then, based on the given information, you can write:
car speed = 80 km/4 h = 20 km/h
truck speed = 50 km/2 h = 25 km/h
The velocity includes, besides the speed, the direction of the motion, both car and truck move to the south, then:
car velocity is 20 km/h to the south
truck velocity is 25 km/h to the south
Then, you can conclude:
truck moves faster than car (truck is 5 km/h faster than car)