【问题】在周长为200米的圆形跑道的一条直径两端,甲、乙两人骑自行车分别以6米/秒和5米/秒的速度同时行驶,一个顺时针,一个逆时针。问:15分钟内,甲、乙两人相遇多少次?【思路点睛】首先统一单位,15分钟=900秒。很容易得到,第一次相遇两人应该是共行100米,以后每次相遇都是两人共行200米。第一次相遇需要的时间是:100÷(5+6)=100/11(秒)。以后每次相遇的时间都是:200÷(5+6)=200/11(秒)。去掉第一次相遇所用的时间,还剩下 [Question] At both ends of a diameter of a circular runway with a circumference of 200 meters, both bicyclists A and B drive at speeds of 6 m / s and 5 m / s at a time, one clockwise and one counterclockwise. Q: In 15 minutes, how many times did A and B meet each other? 【Ideas Dotting】 First, unite the unit for 15 minutes = 900 seconds. It is easy to get the first time they meet two people should be 100 meters, each encounter is 200 meters after the two co-line. The first time needed to meet is: 100 ÷ (5 + 6) = 100/11 (seconds). Each time after the encounter is: 200 ÷ (5 + 6) = 200/11 (seconds). Remove the first encounter time, left