<s>[INST] While Alex is hiking, a thunderstorm approaches. Alex quickly seeks shelter in a small cave in the nearby woods. The cave has only one entrance, a small opening at the bottom of a 6-meter-tall cliff. As the storm intensifies, the wind howls and Alex is startled by frequent lightning. The storm lasts for 35 minutes in the area. From the moment the storm started, every time lightning flashed, Thirteen seconds later, thunder could be heard. When Alex heard the 12th clap of thunder, 156 seconds had passed from when the storm had begun. On average, how many seconds would elapse before lightning was visible to Alex, assuming it was not obscured?[/INST]