On the double track railway, there are two fast and slow trains, both 250m long, running in the same direction at the speed of 50km / h and 45km / h respectively How much time do they overtake? Use the system of linear equations with one variable to solve!

Let the overtaking time be X
50X-0.25=45X
X = 0.05 hours
That's three minutes

If a train passes through a 1200m long railway bridge at a speed of 72km / h and the time taken for the whole train to completely cross the bridge is 84s, the length of the train is m. The time for the whole train to travel completely on the bridge is s．

(1) The speed of the train v = 72km / h = 20m / s, ∵ v = St ∵ the total distance of the train: S = VT = 20m / s × 84s = 1680m, the length of the train: s car = S-S bridge = 1680m-1200m = 480m; (2) the distance of the train running completely on the bridge: s' = s bridge-s car = 1200m-2 × 480m = 240m, ∵ v = St ∵ the train is finished

Nanjing Yangtze River Bridge is 1600m long. The time for a 250m long train to pass through the main bridge at a uniform speed is 3min5s. The time for the train to travel on the main bridge is calculated
The format is 1. Known 2. Ask 3. 4. Answer

First, the speed of the train
The actual length of the train from entering the main bridge to leaving the main bridge is as follows:
1600 + 250 = 1850m, 185s, so the train speed is (1600 + 250) / 185 = 10m / s
Then we can find the running time of the train on the main bridge
The actual running length of the train is 1600-250 = 1350m
Using length / speed = time, we can get
The time of all trains running on the main bridge is as follows:
t=1350/10=135s

The main bridge of Nanjing Yangtze River Bridge is 1660 meters long. The time for a 250 meter long train to pass through the main bridge at a constant speed is 3 minutes and 5 seconds

S = l Car + L bridge = 250m + 1660m = 1910m (the total distance of the car) v = s / T = 1910m / 3min5s ≈ 10.3m/s (the speed of the car) s' = l bridge - L car = 1660m-250m = 1410m (the distance of the car completely on the bridge) t '= s' / v = 1410m / 10.3m/s ≈ 136.9s (the time of the car completely on the bridge)

How many seconds does it take for a 150m train to pass through the main bridge of Nanjing Yangtze River Bridge with a total length of 1577m at a speed of 15mgs
It's better to have a problem-solving process, OK, I will add points!

Because the train has its own length, the total distance it passes is the length of the bridge plus the length of the train
It is known that S1 = 150m, S2 = 1577m, v = 15m / s
Ask: T =?
s=s1+s2=150m+1577m=1727m
According to the formula: v = s / T: T = s / v = 1727m / 15m / s ≈ 115.13s
A: it takes about 115.13 seconds

How much time does it take for a train to cross the Yangtze River Bridge at a full speed of 157 meters per second?

When passing completely, the distance traveled by the front of the car is 1577 + 150, and 150 is the length of the car body
So the time is:
(1577 + 150) / 15 = 116 seconds

When a train passes through a railway bridge, it takes 30s from the bridge to the end of the bridge, while the time of the whole train on the bridge is 20s. If the train speed is 20m / s, the length of the railway bridge is 20 seconds m. The conductor is m．

Let the length of the railway bridge be XM and the length of the train be YM. From the meaning of the question, we get x + y = 30 × 20x − y = 20 × 20, and the solution is x = 500y = 100. Answer: let the length of the railway bridge be 500m and the length of the train be 100m. So the answer is: 500100

The length of a railway is YM, and the length of a train is XM. It takes 30s from the bridge to the end of the bridge, while the time of the whole train on the bridge is 20s
20 m / s————

Suppose: the speed of the train is v m / s, the meaning of the train completely passing is: from the time when the front of the train just enters the bridge section to the time when the rear of the train just leaves the other end of the bridge, so there is the equation x + y = 30 * v. ① the meaning of the whole train on the bridge is: the time when the rear of the train completely enters the bridge section to the time when the front of the train just leaves the other end of the bridge, so there is the equation

When a train passes a railway bridge, it takes 30 seconds from the bridge to the end of the bridge, while the time of the whole train on the bridge is 20 seconds. If the train speed is 20 meters per second, how long is the bridge?

Train length: (20 × 30) - (20 × 20) = 200m, 200 △ 2 = 100m
Bridge length: 30 × 20-100 = 500m

A 200m long train passes the 1800m long railway bridge at the speed of 20m / s. how long does it take for the train to pass the bridge?

According to the formula: v = st, t = SV = 2000m, 20m / S = 100s. A: it takes 100s for all trains to pass the bridge

On the double track railway, there are two fast and slow trains, both 250m long, running in the same direction at the speed of 50km / h and 45km / h respectively How much time do they overtake? Use the system of linear equations with one variable to solve!