The calculated distance (air line) between Poste de Flacq and Quatre Bornes is approximately 18 miles respectively 29 kilometers.
By car or train, the actual journey to Quatre Bornes is certainly longer, as only the direct route (as the crow flies) between Poste de Flacq and Quatre Bornes has been calculated here.
Air line (approximately)
29 kilometers
15 nautical miles