The calculated distance (air line) between Sŭngho 1-tong and Pyongyang is approximately 12 miles respectively 20 kilometers.
By car or train, the actual journey to Pyongyang is certainly longer, as only the direct route (as the crow flies) between Sŭngho 1-tong and Pyongyang has been calculated here.
Air line (approximately)
20 kilometers
11 nautical miles