The problem statement:
Distance between two stations A and B is 230 km. Two motorcyclist starts simultaneously from A and B in opposite directions and the distance between them after 4 hours is 50 kms. Speed of each of them in km/hr is:
$$ (a) 40, 30 \quad \quad (b)27, 17 \quad \quad (c) 50,40 \quad \quad (d)None $$
The suggested answer is (a) and in the solution it is stated that "Total distance covered here is $280$ kms $(230+50)$ and not $180$ kms $(230-50)$".
But I am not getting this reasoning, could somebody explain me why are we adding instead of subtracting?