Seven cosmonauts are exploring a little spherical asteroid.
Cosmonaut A walks 30 km in one direction, turns 90 degrees to his left,
again walks 30 km in the new direction, then turns again 90 degrees left
and walks again 30 km in that new direction.
does exactly the same except each walk is 40 km
(that is walks 40 km, turns left, 40 km, turns left, 40 km).
Cosmonauts C, D, E, F, G also do the same except they walk every segment
50 km, 60 km, 70 km, 80 km and 90 km.
All the Cosmonauts start in different directions from the same point and end their walk
also at a same point except one of them.
Which one and where is he with respect to the others ?
What is the size of this asteroid ?