The distance is the same in both instances.
Speed =distance/time
So distance=speed x time
Let's assume the jet took t hours from X to Y, it took t+0.5 hours from Y to X
Equate distance (speed x time) from X to Y to that from Y to X
480t=460(t+0.5)
480t=460t+230
20t=230
t=11.5hours
t+0.5=12hours(Hours taken to fly from Y to X)
Distance=speedxtime
=460x12
=5520m