The calculated distance (air line) between Wezembeek-Oppem and Seraing is approximately 47 miles respectively 76 kilometers.
By car or train, the actual journey to Seraing is certainly longer, as only the direct route (as the crow flies) between Wezembeek-Oppem and Seraing has been calculated here.
Air line (approximately)
76 kilometers
41 nautical miles