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When a train enters a 300m long tunnel, it takes 20s from entering the tunnel to leaving completely. The time for the train to be completely in the tunnel is 10s
Let the length of the train be XM. According to the constant speed, the equivalent relationship is listed: 300 + X20 = 300 − X10, the denominator is removed to get 300 + x = 600-2x, the items are combined to get 3x = 300, and the solution is x = 100. Then the length of the train is 100m
It takes 15 seconds for the train to pass the 300 meter long tunnel and 12 seconds for the train to pass the 180 meter long bridge______ Rice
(300-180) / (15-12) × 15-300, = 40 × 15-300, = 300 (m)
A train with a total length of 240 meters, 30 meters per second, has to pass through a 570 meter long bridge,
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（240+570）/30=27
There is a kind of rectangular ceramic tile. If they are used to lay a square floor, the minimum side length of the square floor is 180cm; if it is divided into small square tiles, the side length of the small square tiles is 4cm at most. What kind of ceramic tile is this?
If they are used to make a square floor, the minimum side length of the square floor is 180cm; if they are divided into small square tiles, the side length of the small square tile is 4cm at most, that is, the minimum common multiple of the length and width of the tile is 180, and the maximum common divisor is 4, So this is a 9 cm long and 5 cm wide ceramic tile
The practical problems about the surface area of solid figure in Grade 6
In the sixth grade, the three-dimensional graphics are mainly cylinder and cone. The surface area is mainly the surface area of the cylinder, and then the surface area of the cylinder. The main purpose is to distinguish the area of those surfaces. For example, the chimney only needs the side area, the water bucket needs the side area plus one bottom area, and the steam oil bucket needs the side area plus two bottom areas. After mastering these knowledge, you can use the formula to calculate
Sixth grade graphic calculation problems
The length, width and height of a cuboid are a, B and C respectively. The cuboid volume is 60 cubic centimeters, and the square of (3a-4b) is 0
From the known
abc=60
3a-4b=0
5b-3c=0
The solution is a = 4, B = 3, C = 5
So the surface area is 94 square centimeters
Application of graphic area
If the bottom of the original parallelogram is 24 cm and the height is 6 cm, what is the area of the parallelogram?
I want the process
The diagonal connecting the original parallelogram
……
The edges of the new parallelogram are the median lines of the triangles
So the new area is half the old one
=24 * 6 / 2 = 72 square centimeter
Solving mathematical practical problems (primary school)
The distance between the two places is 350 km. The express train and the local train depart from the two places at the same time and meet each other after 3.5 hours. It is known that the speed ratio of the express train and the local train is 3:2. What is the speed of the two trains?
The proportion that can be listed is better,
350 / 3.5 = 100 [speed and speed]
100 / (3 + 2) * 2 = 40 [idle]
100-40 = 60 [express]
It takes 10 hours for a bus to go from city a to city B, and 15 hours for a truck to go from city B to city A. the two cars leave each other at the same time. When they meet, the bus is 240 kilometers away from city B. how many kilometers are there between city a and city B?
A: the distance between city a and city B is 600 km
The stationery store bought 100 pens at the price of 4 yuan each, and sold them at 6 yuan each. When a part of them was sold according to the marked price, they were sold at a 10% discount. After they were sold out, the store made a total profit of 188 yuan?
X pens with discount
So the 10% discount selling price is 5.4 yuan, and the profit is 1.4 yuan
The total profit is:
1.4x+2×（100－x）＝188
x＝20
So there are 20 on sale
RELATED INFORMATIONS
- 1. It takes 56 seconds for a train to pass a 240 meter bridge, and 48 seconds for a train to pass a 144 meter tunnel at the same speed There are detailed formulas
- 2. It takes six seconds for a train to pass by a power pole on the side of the road. It takes 46 seconds for a train to cross a 2000 meter long bridge at the same speed. How long is the train
- 3. It took 24 seconds for a train to pass through the first tunnel with a length of 360 meters, and then it took 16 seconds to pass through the second tunnel with a length of 216 meters. This train is facing another train with a length of 75 meters and a speed of 86.4 kilometers per hour. What is the time for the wrong train to cross?
- 4. A train passes through two tunnels at the same speed. The first 420 meters takes 27 seconds, and the second 480 meters takes 30 seconds?
- 5. Grade 5 math problem: a train passes through two tunnels at the same speed. One tunnel is 420 meters long and runs for 27 seconds. The other tunnel is 480 meters long and runs for 30 seconds How long is the train
- 6. A 240 meter long train passes through an 881 meter long tunnel at a speed of 1500 meters per minute. How many minutes does it take from the front of the train to the rear of the train to leave the tunnel?
- 7. A train passes through a 450 meter long tunnel at a speed of 18 meters per second. It takes 35 seconds from the front of the train entering the tunnel to the rear of the train leaving the tunnel to calculate the length of the train
- 8. A train through the tunnel, from the front into the tunnel to the rear out of the tunnel takes 1 minute and 30 seconds, the known speed of the train is 100 km
- 9. It takes 50 seconds for a 1000m bridge and 70 seconds for a 1500m bridge. If the speed of the train is reduced by 20%, how much does it take for the train to pass through the 1950m long tunnel [solve with the equation of one variable and one degree]
- 10. It takes 24 seconds for the first 360 meter tunnel and 16 seconds for the second 220 meter tunnel
- 11. It takes 20s for a train to pass through a 300m tunnel. The tunnel light shines on the train for 10s. Ask the conductor
- 12. A train runs at a speed of 72km / h, and there is a tunnel directly in front of it. The train must whistle before entering the tunnel. The driver hears the echo reflected from the cliff at the tunnel entrance after 1.5s. How far is the driver from the tunnel when he hears the echo? (sound speed is 340m / s)
- 13. Wang Xiaoya was riding on a 200m long train with a speed of 72km / h. from the window, she could see the train running head-on Wang Xiaoya was riding on a 200m long train running at a constant speed of 72km / h. from the window, she saw a 300m long freight train coming in front of her. The passing time was 10s, so she calculated the speed of the freight train
- 14. A train is 200 meters long and has to pass through a 300 meter long tunnel. How many meters does the train travel from the front to the rear of the train?
- 15. A train runs at a constant speed through a 500m long tunnel, If it takes 30 seconds for the train to enter the tunnel and leave the tunnel completely, and the time for the whole train to be in the tunnel is 20 seconds, the length of the train can be calculated Using equation
- 16. It took 50 seconds for a train to pass through a 1140 meter long bridge (from the front of the train to the rear of the train leaving the bridge), and 80 seconds for the train to pass through a 1980 meter long tunnel?
- 17. A certain section of railway is made up of L-length rails one by one. When a train is moving at a constant speed, a passenger in the train needs to measure the speed of the train. He has measured that the time interval of N consecutive vibrations when the train passes through the rail joint is t, then the relationship V of the speed V is calculated=
- 18. 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!
- 19. A freight car is running on the straight road at the speed of V1 = 28.8km/h. Due to the wrong scheduling, a passenger car behind it is driving on the same road at the speed of V2 = 72km / h. at the distance of S0 = 600m, the driver of the passenger car immediately stops the truck. In order to avoid collision, at least how much speed should the passenger car speed up?
- 20. A train with a length of 300m crosses the bridge at a speed of 36km / h. It is known that it takes 5min for all trains to pass through the bridge, so the bridge length can be calculated rt