In the line test, travel questions are a very common type of questions, and the encounter and chase questions are the key basic models of travel questions, and candidates need to be proficient in them. Let's take a look at such questions.
First, the problem of encounters
Meaning: Two objects start from two places at the same time, travel in the opposite direction, and after a period of time, they will inevitably meet on the way, this type of question is called an encounter problem. That is, A goes from A to B, and B goes from B to A, and the two set off at the same time and go in the opposite direction, and then meet on the way, in essence, A and B have walked the distance between A and B together, then.
The distance of the encounter and = the distance traveled by A + the distance traveled by B.
The speed of A and the time of the encounter + the speed of B the time of the meeting.
A's velocity + B's velocity) The time of the encounter.
Speed and time of encounter.
In general, the relationship between the encounter problem is: distance sum = speed and meeting time.
Second, the problem is pursued
Meaning: There is a certain distance between two objects, and they start in the same direction at the same time, and the faster one catches up with the slower one behind, and after a period of time, they will inevitably catch up. That is, A sets off from place A, B sets off from place B, and the two of them set off at the same time and go in the same direction, and A chases after B and A is faster than B, and catches up with B after a period of time.
Catch up distance difference = distance traveled by A - distance traveled by B.
A's velocity catch-up time - B's velocity catch-up time.
A's velocity - B's velocity) catches up with time.
Speed difference catch-up time.
In general, the relationship between the catch-up problem is: the difference in the distance = the difference in speed and the time of the catch-up.
Let's use the example questions to consolidate what we have learned today!
Example 1] A and B are walking in opposite directions from two places 2000 meters apart at the same time, A travels 55 meters per minute, B travels 45 meters per minute, if a dog and A travel in the same direction at the same time, 120 meters per minute, after encountering B, immediately turn back and run towards A, and then run to B when encountering A. This goes on and on until A and B meet, and the distance the dog has traveled is ( ) meters.
a.800 b.1200 c.1800 d.2400
Answer] d. Analysis] The running time of the dog is the time taken by A and B to meet, let the meeting time be t, 2000=(55+45) t can be obtained from the title, and the solution is t=20, then it is 20 120=2400 meters.
Example 2] There is a pedestrian and a cyclist both moving from A to B at a speed of 36 km for 10 km8 kilometers per hour, at this time, there is a train on the side of the road also speeding from A to B, the train takes 22 seconds to overtake pedestrians, and 26 seconds to overtake cyclists, the body length of this train is ( ) meters.
a.232 b.286 c.308 d.1029.6
Answer] B. Analysis] The speed of the pedestrian = 36 km-h = 1 m-s, cyclist's speed = 108 km-h=3m-s, let the train speed be v, then 22 (v-1)=26 (v-3) can be obtained from the title, and the solution v=14, the length of the train body is 22 (14-1)=286 m.
Today's study is here first, friends must do more questions to consolidate the knowledge learned today!