Final answer:
The relative speed of the two cars is 80 km/h.
Step-by-step explanation:
The relative speed of two objects is the difference in their individual speeds when they are moving relative to each other. To find the relative speed in this scenario, we need to calculate the total speed of both cars. Let's assume the positive direction is east.
Car A is moving at 45 km/h east and Car B is moving at 35 km/h west. Since both cars are moving in opposite directions, we subtract the speeds:
Relative speed = Speed of Car A - Speed of Car B
Relative speed = 45 km/h - (-35 km/h)
Relative speed = 45 km/h + 35 km/h
Relative speed = 80 km/h