The calculated distance (air line) between Duisburg and Bochum-Hordel is approximately 18 miles respectively 29 kilometers.
By car or train, the actual journey to Bochum-Hordel is certainly longer, as only the direct route (as the crow flies) between Duisburg and Bochum-Hordel has been calculated here.
Air line (approximately)
29 kilometers
16 nautical miles