教材上有这样一道应用题：运动场的跑道一圈长400m．甲练习骑自行车,平均每分钟骑350m,乙练习跑步,平均每分钟跑250m．两人从同一处同时反向出发,经过多少时间首次相遇?又经过多少时间再次相遇?解完这道习题后,我想,如果把题中的“反向”改为“同向”,结果会怎样呢?首先,我想到了设直接未知数．解法1设经过x分钟首次相遇(实质是追 There is such an application question on the textbook: The track of the stadium is 400m long. A practice cycling, riding 350m per minute, B practice running, running an average of 250m per minute. How do they meet each other for the very first time and how much time has they met again? After solving this problem, I thought that if we change the “reverse” of the question to “same direction”, the result will be the same. What would happen? First, I thought of setting the direct unknown. Solution 1 is set to meet for the first time in x minutes (essentially to recover