Train a and B are going towards each other at the same speed. A whistle for 4 seconds. The people in train B hear it. Another 20 seconds later, the two cars meet. What is the distance between the two cars when car a whistle

Train a and B are going towards each other at the same speed. A whistle for 4 seconds. The people in train B hear it. Another 20 seconds later, the two cars meet. What is the distance between the two cars when car a whistle

Let s be the distance between the two cars when car a beeps, and V be the same speed of the two cars, because when the person in car B hears car a's whistle after 4 seconds, so s = 340 * 4 + 4V, the two cars meet again after 20 seconds, that is, the two cars meet 24 seconds after the whistle, so s / 2 = (4 + 20) V solve the above two equations, we can get s = 16320 / 11V = 340 / 11

A and B trains travel from two places 400 kilometers apart at the same time. A trains 58 kilometers per hour and 62 kilometers per hour. A few hours later, the two trains are 160 kilometers apart

After t hours, the distance between the two vehicles is 160 km
(58+62)t = 400 ± 160
120t = 400 ± 160
T1 = 2 hours (this value is before the encounter, 160 km apart)
T2 = 4 and 2 / 3 hours (this value is after the meeting, 160 kilometers apart)

The two trains run in opposite directions. Car a travels 50 kilometers per hour, and car B 58 kilometers per hour. When the two trains cross each other, a passenger on car a passes a total of 10 seconds from the front to the rear of car B, and car B has a total length of () meters

Length = 10 × (50 + 58) △ 3600 × 1000 = 300m

At the same time, the train runs from two places, with a speed of 58 km / h and B speed of 62 km / h. The two trains meet at 40 km from the midpoint. How many kilometers is the distance between the two places
The question is "how many kilometers are there between the two places?

40*2/(62-58)*(62+58)=80/4*120=20*120=2400(km)