![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
A train travels at an average speed. It takes 20s to pass through a 300m long tunnel. There is a lamp on the top of the tunnel, and the time on the train is 10s. Ask for the speed of the train A series of univariate linear equations
Let the train length L speed V then
(300 + L) / v = 20 and L / v = 10
300/V=10
V=30
Hu train speed is 30m / s
A train travels at a constant speed through a 300m long tunnel Write clearly, especially the symbols! "It takes 20 seconds. There is a lamp on the top of the tunnel, which shines vertically downward, and the time when the light shines on the train is 10 seconds. According to the above data, can you calculate the length of the train? If so, what is the length of the train? If not, please explain the reason."
Let the length of the train be y and the speed of the train be X. set the following equation:
{20x=300+y
{10x=y
Solve the equation: x = 30, y = 300
So the length of the train is 300m
A passenger car and a freight car leave from both places at the same time. When the two trains meet, the passenger car takes 70% of the whole journey, and the freight car is still far from the midpoint 320 kilometers. It is known that it takes 20 hours for the bus to complete the whole journey. How many kilometers does the bus travel per hour?
A passenger train and a freight train leave from Party A and Party B at the same time. When the two trains meet, the passenger train takes 70% of the whole journey,
Distance ratio between passenger and freight = 7:3, distance between freight cars: midpoint: whole journey = 7-5: 10 = 2:10 = 1:5
The truck is 320 km away from the midpoint. The whole journey = 320 x 5 = 1600km
It is known that it takes 20 hours for the bus to complete the whole journey. How many kilometers does the bus travel per hour?
1600 /20 = 80 km /h
A passenger car and a freight car leave from both places at the same time. When the two trains meet, the passenger car takes 70% of the whole journey, and the freight car is 500 kilometers away from the midpoint of the two places. It is known that the full journey of the passenger car takes 20 hours, and how many kilometers does the passenger car travel per hour?
70%-（1-70%）
=70%-30%
=40%，
five hundred × 2÷40%
=1000÷40%
=2500 (km);
2500 ÷ 20 = 125 (km)
A: the bus travels 125 kilometers per hour
The two trains of Party A and Party B started from the two places with a distance of 1100km at the same time and met after 5 hours. It is known that vehicle a is 1 / 6 slower than vehicle B. what is the speed of vehicle B
Let the speed of car B be x km,
Then the speed of car a is (1-1 / 6) x km
5[x＋（1-1/6)x]=1100
5[x+5/6x]=1100
five × 11/6x=1100
11/6x=220
x=120
（1-1/6)x=100
A: the speed of car B is 120 kilometers
The two trains run from the two places 580km apart and meet after 2.5 hours. It is known that the speed ratio of the two trains is 14:15 What are the speeds? (solved by the equation of proportion)
Let the speed of a be 14x and the speed of B be 15x
（14x＋15x） × 2.5=580
29x × 2.5=580
2.5x=20
x=8
A speed = 14 × 8 = 112 km / h
B speed = 15 × 8 = 120 km / h
RELATED INFORMATIONS
- 1. The length of the two trains a and B is 144m and 180m. Car a runs 4m more per second than car B. the two trains run opposite to each other, and it takes 9s from meeting to staggering. What is the speed of the two trains?
- 2. A bus and a truck run in the opposite direction from the same place at the same time, with a distance of 400 kilometers after 4 hours. It is known that the bus travels 58 kilometers per hour, and how many kilometers does the truck travel per hour?
- 3. A passenger train runs 60 kilometers per hour from city a to city B. after two hours, a train from city B to city a meets in four hours. At this time, the freight train runs three points of the whole journey How many kilometers are the two cities apart
- 4. A 200m long train passes through a 1.6km long bridge at a constant speed of 120s, and the running speed of the train is () A. 15m/s B. 11.7m/s C. 1.7m/s D. 13.3m/s
- 5. It takes 65 seconds for a train to pass through a 1000 meter bridge and 50 seconds if it passes through a 730 meter tunnel at the same speed. Find the forward speed and length of the train
- 6. It takes 52 seconds for a train to pass through a 320 meter long tunnel. When it passes through an 864 meter long bridge, its speed is higher than when it passes through the tunnel It takes 52 seconds for a train to pass through a 320 meter long tunnel. When it passes through a 864 meter long bridge, its speed is 1 / 4 higher than that when it passes through the tunnel. As a result, it takes 1 minute 36 seconds? I've been thinking for a long time. Wuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwuwu To calculate, equation XY has not been taught. Besides, it's arithmetic control.
- 7. It takes 20 seconds for a train to travel at a constant speed through a 450m long tunnel. There is a lamp on the tunnel, and the light shines on the train for 5S Find: (1) the length of the train; (2) The time when the train is completely in the tunnel There is a lamp in the tunnel. The time when the light shines on the train is 5S. What do you mean ////////
- 8. A 100 meter long train passes through an iron bridge at the speed of 36 km / h. The time required for all trains to pass through the iron bridge is 50 seconds. What is the total length of the iron bridge?
- 9. The train runs along the track straight line from ground a to ground B. the distance between B is s. The train starts from ground a and accelerates uniformly. The linear motion acceleration is A1, then decelerates uniformly. The linear motion acceleration is A2. When it arrives at B, it just stands still. Calculate the time t for the train from a to B
- 10. You travel for a week on vacation. The sum of the days of the week is 84. What date did the travel agency send you home?
- 11. It takes 80 seconds for a train to pass through a 199 meter long railway bridge, and 72 seconds for it to pass through a 172 meter long tunnel at the same speed?
- 12. The two trains run at a uniform speed in the same direction. When they start, the slow train is 60 kilometers in front of the fast train. The speed of the slow train is 2 / 5 of that of the fast train. After driving for half an hour, the fast train catches up with the slow train. Q: what are the speeds of the two trains?
- 13. The fast and slow trains run opposite each other. The fast train is 50 meters long and the slow train is 80 meters long. The speed of the fast train is twice that of the slow train. If the time for people sitting on the slow train to see the fast train passing through the window is 5 seconds, then the time for people sitting on the fast train to see the slow train passing through the window is 5 seconds______ Seconds
- 14. An expressway is 336 kilometers long. A passenger car completes the whole journey in 3.2 hours and a truck completes the whole journey in 4.8 hours How fast is the bus faster than the truck?
- 15. Li Yun sat in a train with a speed of 60 kilometers per hour by the window and saw a truck with 30 carriages coming head-on. When the front of the truck passed the window, he began to remember the time. Until the last carriage passed the window, the recorded time was 18 seconds. It is known that each carriage of the truck is 15.8 meters long and the distance between the carriages (including the front) is 1.2 meters, The front of the truck is 10 meters long. What is the speed of the truck?
- 16. A and B are 540 kilometers apart. A bus and a truck leave the two places at the same time. The speed ratio is 5:4. They meet in three hours What are the speeds of passenger cars and trucks?
- 17. The passenger and freight cars run from Party A and Party B respectively. The passenger car runs 78 kilometers per hour and the freight car runs 60 kilometers per hour. The two cars meet at 18 kilometers from the midpoint of the whole journey. How many kilometers are there in the whole journey?
- 18. Train a and train B leave from cities a and B along the same railway line. Train a runs 90km per hour and train B runs 110km per hour 12 hours later, the two cars met. On the map with a scale of 1:6000000, how many centimeters is the railway line long? [I don't understand at all. First (90 + 110) divided by 12?]
- 19. The railway from Shanghai to Tianjin is 1325 kilometers long. A train from Shanghai to Tianjin has been running for 5 hours, just 2 / 5 of the whole journey. Drive like this and arrive in Tianjin in a few hours? (in two ways)
- 20. The speed of a passenger car is 60 km / h and the speed of a freight car is 45 km / h. The freight car is 135 meters longer than the passenger car. If the two cars run opposite on the parallel track and the time they spend in the process of meeting is 30 seconds, the lengths of the passenger car and the freight car are ___