In a track and field field, A, B, and C run an 800-meter race along a 400-meter circular track. When A completes one lap, B runs (1/7) more laps than A, and C runs (1/7) laps less than A. If their respective running speeds remain the same, then when B reaches the finish line, how many meters will C be away from the finish line?
在田径运动场上，甲、乙、丙三人沿400米环行跑道进行800米跑比赛．当甲跑完1圈时，乙比甲多跑(1/7)圈，丙比甲少跑(1/7)圈．如果他们各自跑步的速度始终不变，那么当乙到达终点时，丙离终点还有多少米．
<gadget id="calculator">800 - 600</gadget>
<output>200</output>

<result>200</result>