The calculated distance (air line) between Fond du Sac and Poste de Flacq is approximately 12 miles respectively 20 kilometers.
By car or train, the actual journey to Poste de Flacq is certainly longer, as only the direct route (as the crow flies) between Fond du Sac and Poste de Flacq has been calculated here.
Air line (approximately)
20 kilometers
11 nautical miles