例如，在行程问题中有这样一道题：“两辆客车同时从A，B两城相对开出，两

For example, there is a question in the itinerary problem: "Two passenger cars depart from cities A and B at the same time. The two cars meet for the first time at a distance of 50 kilometers from city A. After they meet, they continue to move forward and arrive at the station. Return immediately and meet at 40 kilometers from City B

For example, in the itinerary question there is such a question: "Two buses from A, B two cities at the same time opposite, the two cars first met 50 kilometers from A city, after the encounter continued to move forward, to the station immediately return, return from The City B 40 km to meet."

For example, in the travel problem, there is such a question: "two buses leave city a and city B at the same time. For the first time, the two buses meet at a distance of 50 km from city A. after meeting, they continue to move forward, return immediately after arriving at the station, and meet 40 km away from city B when returning<br>