Xiao Jing and Xiao Bei set off at the same time at the same place and in the same direction, running at a constant speed along the circular track. If Xiao Bei's speed is 2.5 times that of Xiao Jing's at the start, when Xiao Bei catches up with Xiao Jing for the first time, Xiao Jing's speed will immediately increase by 25%, while Xiao Bei's speed will immediately decrease by 20%. It is known that the place where Xiaobei catches up with Xiaojing for the second time is 100 meters away from the place where Xiaobei catches up with Xiaojing for the first time, so what is the circumference of this circular runway in meters?
小京和小北两人同时同地同向出发，沿环形跑道匀速跑步．如果出发时小北的速度是小京的2.5倍，当小北第一次追上小京时，小京的速度立即提高25%，而小北的速度立即减少20%．已知小北第二次追上小京的地点与第一次追上小京的地点相距100米，那么这条环形跑道的周长是多少米．
<result>300</result>