Because the tram runs every 5 minutes, the whole journey takes 15 minutes. The tram that cyclists saw in bilibili was sent out 15 minutes ago. It can be inferred that when he started from bilibili, the fourth tram started from Station A, and during the period from bilibili to Station A, the tram from Station A arrived at 12. There are 9 trams with 8 intervals. So: 5× 8 = 40 (minutes).