Three people are running. When A completes 5 laps, B completes 4 laps; when B runs 6 laps, C runs 5 laps. If three people start from the same place at the same time, how many laps does C run when the three meet at the starting point?
三人跑步，甲完成5圈时，乙完成4圈；乙跑了6圈时，丙跑了5圈．若三人同时同地出发，三人在出发处相遇时，丙跑了多少圈？
<result>10</result>