When A train travels south from station A to station B with a speed of 70 km hr along a straight path in one and half hours What is the displacement of the train when it travels from station A to sta?

I am wary of answering questions like this directly because they look as if from a school pupil wanting us to do his or her homework.

Therefore I will tell you only how to answer it, which I think is the point.

Firstly, reject that data about direction. It misleads you into thinking, "Ah, co-ordinates" but since there is no further information in that regard we can treat the track's course as a red herring which we ignore.

The train is travelling for 1.5 hours at a steady 70km/hr.

Distance is the product of time and speed, and simple dimensional analysis shows that here, the answer will be xkm.

Come back when you've achieved a First-class Honours Degree in Mathematics!