The calculated distance (air line) between Montblanc and L'Hospitalet de Llobregat is approximately 49 miles respectively 78 kilometers.
By car or train, the actual journey to L'Hospitalet de Llobregat is certainly longer, as only the direct route (as the crow flies) between Montblanc and L'Hospitalet de Llobregat has been calculated here.
Air line (approximately)
78 kilometers
42 nautical miles