Summary and Expansion of Seven Classical Topics on Travel Problem Simply categorize travel problems: (1) Encountering and pursuing problems on straight lines (including multiple round-trip encounters and pursuits) (2) Train crossing, bridge crossing and wrong train (3) Travel problem among multiple objects (4) Ring Problem and Clock Problem (5) Flow and sailing problems (6) Variable Speed Problem Some habitual solutions: (1) Using the method of setting numbers and dealing with the number of shares (2) Segmental processing using velocity variation (3) Comparing and splitting the shaperange process by using sum-difference multiplier and proportional relation (4) Solving by Equation Method 1. Meeting and pursuing on a straight line The encounter and pursuit on the straight line are the most basic two kinds of problems in the process of travel. The solution of these two kinds of problems can be said to be the basis of solving most of the travel problems. Exemplary 1. A and B two cars drive from east to west at the same time. A travels 56 kilometers per hour and B travels 48 kilometers per hour. The two cars meet at 32 kilometers from the midpoint of the two places.Q: How many kilometers is the distance between East and West? Two swimmers swam back and forth in a 30-meter-long swimming pool. The speed of A was 1 metre per second and that of B was 0.6 metres per second. They swam back and forth for 5 minutes from both ends of the pool.How many times did the two meet in this period, regardless of the turning time? 2. Train Crossing, Bridge Crossing and Miscarriage In the train problem, there is nothing special about speed and time. The special place is distance.Because the distance at this time is not only related to the distance of the train, but also to the length of the train, tunnel and bridge. Here's how to solve the problem of train crossing braking.Ha ha ~ ~ bridge by static This type of topic seems complex and dazzling. In fact, we can use static braking to look at the whole journey of the locomotive or tail.When there are many variables (train passing, two trains moving side by side, tail by side, etc.), one of them can be regarded as static. It is easy to solve the problem by studying the stroke of another variable and the speed difference or speed difference between the two variables. Example 3. It takes 25 seconds for a bus to pass through a 250-meter-long tunnel and 23 seconds for a 210-meter-long tunnel.It is known that in front of the bus there is a truck with the same direction. Its body length is 320 meters and its speed is 17 meters per second.Find out the time it takes for the train to leave when it meets the truck. Exemplary 4. A PLA troop is 450 metres long and travels at a speed of 1.5 metres per second.How long does it take for a soldier to go from the tail of a platoon to the head of a platoon at a speed of 3 meters per second and return immediately to the tail of a platoon?(This question is superclassic ~) Exemplary 5: There are two trains running in the same direction at the same time. After 12 seconds, the express train exceeds the slow train. It is known that the fast train runs 18 meters per second and the slow train runs 10 meters per second. How long is the body length of the fast train?If the two trains run in the same direction at the same time with the same tail, the fast train will overtake the slow train in 9 seconds, then what is the length of the slow train body? (Head-to-head, tail-to-tail, full exercise to solve problems by static braking, and head-to-head and head-to-tail contact two types of oh-to-think.) Supplementary Question: It takes 6 seconds for a train to pass through a 400-metre-long bridge, and 4 seconds for the body to be completely on the bridge to calculate the speed of the train. Travel Problem Among More than 3 Objects Although there are at least three objects involved in this kind of problem, in actual analysis, three or four objects are not analyzed at the same time, but two or two objects are compared.Therefore, the key to solving this kind of travel problem lies in whether the relationship between two objects can be transformed into conclusions related to other objects. Exemplary 6. There are three persons: A, B and C. A walks 100 meters per minute, B walks 80 meters per minute and C walks 75 meters per minute.Now, A is from Dongcun, B and C are from Xicu