A and B are standing at a distance of 20 km
from each other on a straight East-West road.
A and B start walking simultaneously eastwards
and westwards respectively and both
cover a distance of 5 km. Then A turns to his
left and walks 10 km. B turns to his right and
walks 10 km at the same speed. Then both
turn to their left and cover a distance of 5 km
at the same speed. What will be the distance
between them ?