The distance is 510³ m.
In 3 minutes the geese fly: 510² - 510 = 510 ( 510 - 1 ) = 510 * 509 m
510³ : ( 510 * 509 ) = 510² : 509 ≈ 511
511 * 3 min = 1,533 min : 24 = 25 h 33 min
25 h 33 min = 24 h + 1 h 33 min.
The geese will reach home at 12 hours and 3 minutes next day.