There are two trains, one is 130m long and the speed is 23m / S; the other is 250m long and the speed is 15m / s. now the two trains are facing each other and it is necessary for them to meet and leave______ s．

There are two trains, one is 130m long and the speed is 23m / S; the other is 250m long and the speed is 15m / s. now the two trains are facing each other and it is necessary for them to meet and leave______ s．

According to the meaning of the question, we can get: (130 + 250) △ 23 + 15, = 380 △ 38, = 10 (s)

There are two trains, one is 320 meters long, 18 meters per second, and the other is coming at the speed of 22 meters per second. It takes 15 seconds for the two trains to meet and leave each other

Answer: 280 meters
Analysis: if one train is relatively static, the speed of the other train relative to the train is 40 m / s, and the two trains share 15 seconds from meeting to leaving, then the distance s of the other train is 40 m / s × 15 m = 600 m, which is the total length of the two trains, so the length of the other train is L = 600-320 = 280 M

The train is 150 meters long and the speed is 60 / hour. The truck is 120 meters long and the speed is 75 / hour

The sum of the distance between the two vehicles is 150 + 120 = 270
270 / (60 + 75) = 2 hours
So it takes two hours from the front to the rear

A passenger car and a freight car start from two cities at the same time. They travel in opposite directions. The passenger car travels 60 kilometers per hour and the train 45 kilometers per hour
1. A passenger car and a freight car start from two cities at the same time and travel in opposite directions. The passenger car travels 60 kilometers per hour and the train 45 kilometers per hour. When the two cars meet, the passenger car travels 22.5 kilometers more than the freight car. How many kilometers are there between the two cities?
2. When the fifth grade students go for a spring outing, if each car takes 45 people, it's just one more than the original number of cars ordered. If each car takes 50 people, it's just one less than the original number of cars ordered. How many students are there in the fifth grade?
3. If Xiaoya borrows a book from the library, if she reads 40 pages a day, she will finish it two days earlier than the specified borrowing period. If she reads 30 pages a day, she will finish it one day later than the borrowing period. How many days is the borrowing period?
The first one has been answered. Just answer the last two,

2. There are 900 people in total, and there are x people in total. If y cars are planned, then 45 (y + 1) = x; 50 (Y-1) = x, then x = 900; y = 19
3. The loan period is 11 days. If the loan period is x days, we can get 40 (X-2) = 30 (x + 1) and x = 11