(c) $150km/h$ westward
Work Step by Step
Car A is moving eastward with speed = $85km/h$ Car B is moving westward with speed = $65km/h$ The velocity of car B measured by driver in car A = $85+65=150km/h$ westward. For the driver in the car A he is at rest . Since both cars are moving in opposite directions, the speed of car B for him is the sum of speed of car A and car B moving westward. (c) 150 km/h westward is the answer.