[EN] A brain teaser.

Here is a road with a straight portion,up and down.
A particular vehicle will travel through straight with a velocity of 63 km/h, 56 km/h through up and 72 km/h through down.
The car takes four hours time to travel from A to B, and takes four hour and 40 min. to travel back, that is from B to A.
Then the question is what is the distance between A to B ?