A, B, and C are running back and forth on a 240-meter-long runway. A runs 4 meters per second, B runs 5 meters per second, and C runs 3 meters per second. If the three start from one end at the same time, how many When did the three of them start from here at the same time?
甲、乙、丙三人在一条长240米的跑道上来回跑步，甲每秒跑4米，乙每秒跑5米，丙每秒跑3米，若三人同时从一端出发，再经过多少时间三人又从此处同时出发？
<result>28_800</result>