The calculated distance (air line) between Gan Yavne and Bet Shemesh is approximately 17 miles respectively 28 kilometers.
By car or train, the actual journey to Bet Shemesh is certainly longer, as only the direct route (as the crow flies) between Gan Yavne and Bet Shemesh has been calculated here.
Air line (approximately)
28 kilometers
15 nautical miles