The speed of car a from a to B is 60km / h, and that of car B from B to a is 90km / h. The distance between the two places is 200km. How far is the place where the two cars meet from a?

The speed of car a from a to B is 60km / h, and that of car B from B to a is 90km / h. The distance between the two places is 200km. How far is the place where the two cars meet from a?

80 km. The time when the two cars meet is 200 / (90 + 60) = 4 / 3 hours, multiplied by the speed of car a, the answer is 80

If the train speed reaches 150km / h, is "150km / h" the average speed or the instantaneous speed?
When it reaches 150km / h, doesn't it mean that the highest speed is 150km / h? Isn't the highest speed the instantaneous speed? For example, the speed limit on the highway,

This really refers to instantaneous speed
The train speed reaches 150 km / h, which means that the train speed reaches 150 km / h at a certain time

It is known that the three stations a, B and C are in the same straight line. A train runs from station a to station C via station B. the train speed is m km / h. The distance between station a and station B is 200 km. The fire is very serious
When the train leaves station B, the train leaves station a () km after n H

200+mn

As shown in the figure, a and B are 200km apart. A train starts from B and runs at 120km / h along BC direction. In the process of running, the functional relationship between the distance y (km) of the train from a and the running time t (H) is______ ．

∵ A and B are 200 km apart. A train starts from B and runs along BC direction at a speed of 120 km / h. The functional relationship between distance y (km) from a and travel time t (H) is y = 200 + 120 t (t ≥ 0). Therefore, the answer is y = 200 + 120 t (t ≥ 0)