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A and B trains run from 822 kilometers apart at the same time. A trains 65 kilometers per hour, B trains 72 kilometers per hour. A few hours later, the two trains meet?
822 (65 + 72) = 822 (137) = 6 (hours). A: the two cars meet in 6 hours
A. The distance between B and a is 1890 km. The trains a and B start from a and B at the same time and run in opposite directions. A runs 120 km per hour and B 150 km per hour. After how long, the distance between the two workshops is 135 km?
In the problem of travel, distance = speed × time. Suppose that after X hours, the distance between the two vehicles is 135 km, then a has driven 120x km and B has driven 150x km. When the distance between the two vehicles is 135 km before meeting, the equation is: 120x + 135 + 150x = 1890. When the distance between the two vehicles is 135 km after meeting, the equation is: 120x + 150x = 1890 + 135 Or 7.5 hours, the two trains are 135 kilometers apart
A. The distance between B and B is x km. The two trains of a and B leave each other at the same time. Car a runs 120 km per hour and car B runs 100 km per hour. The problems are as follows
When they meet, the distance ratio of the two cars is []: [], and the time ratio is []: []
When two cars travel completely, the distance ratio is []: [], and the time ratio is []: []
Time for meeting t = x / 220
х a mileage = 120x / 220,
B mileage = 100x / 220
The mileage ratio is (120x / 220): (100x / 220) = 6:5
Time: 1:1
The ratio of the whole journey is 1:1
The time ratio is (x / 120): (x / 100) = 5:6
Do with the proportion of primary school students: the time is fixed; the distance ratio is equal to the speed ratio; the distance is fixed, and the speed is inversely proportional to the time
When the two cars meet, the distance ratio is [6]: [5], and the time ratio is [1]: [1].
When two cars travel a full distance, the distance ratio is [1]: [1], and the time ratio is [5]: [6].
A and B are 240 kilometers apart. A and B leave from a and B at the same time. They meet 32 hours later. It is known that the speed ratio of a and B is 3:2. What are the speeds of the two vehicles?
The sum of the speed of the two cars: 240 △ 32 = 160 (km) the speed of car a is 160 × 33 + 2 = 160 × 35 = 96 (km) the speed of car B is 160-96 = 64 (km) a: the speed of car a is 96 km / h, and the speed of car B is 64 km / h
The second radical addition and subtraction method of junior three mathematics
① Given x = radical 7 / 2 - radical 5 / 2, y = radical 7 / 2 + radical 5 / 2, find the value of X / y + Y / X
This is a calculation body, the process should be detailed
X / y = ((root 7-root 5) / 2) * (2 / (root 7 + root 5)) = (root 7-root 5) / (root 7 + root 5) y / x = ((root 7 + root 5) / 2) * (2 / (root 7-root 5)) = (root 7 + root 5) / (root 7-root 5) x / y + Y / x = (root 7-root 5) / (root 7 + root 5) + (root 7 + root 5) / (root 7-root 5) = (...)
x/y+y/x
=(x^2+y^2)/(xy)
=[(x+y)^2-2xy]/(xy)
=[(x+y)^2/(xy)]-2
=[7/(1/2)]-2
=12
X ^ 2 = 7 / 4 + 5 / 4 - follow 35 / 2 y ^ 2 = 7 / 4 + 5 / 4 + follow 35 / 2
xy=7/4-5/4=1/2
x/y+y/x=(x^2+y^2)/xy=6*2=12
The above answer is, root 7 / 2 is called root 7 / 2
If 2 is under the root, the answer is yes
X ^ 2 = 7 / 2 + 5 / 2-radical 35 y ^ 2 = 7 / 2 + 5 / 2 + radical 35
xy=7/2-5/2=1
The final answer is 12 / 1 = 12
x+y=2×√7/2=√7
XY squared difference = 7 / 4-5 / 4 = 1 / 2
The original general division = (X & sup2; + Y & sup2;) / XY
=[(x+y)²-2xy]/xy
=(x+y)²/xy-2
=7/(1/2)-2
=12
The truck team transported 720 tons of Huangsha, two fifths of which were transported three times, each time___ Tons
The truck team transported 720 tons of Huangsha, 2-5 times, each time___ Tons
Xiao Ming's weight was 40 kg the year before last. He lost 1 / 10 of his weight last year. This year, he gained another 1 / 10. This year, his weight is 40 kg___ Kilogram
Each transport of Huangsha = 720 × 2 / 5 △ 3 = 96 tons
This year's weight = 40 × (1-1 / 10) × (1 + 1 / 10) = 39.6kg
There are 87 students in grade 4 and 129 students in Grade 5. There are 24 bottles of mineral water in a box and 6 apples in a box. Is it enough to buy 10 boxes of apples and 9 boxes of mineral water?
Not enough,
There are two grades
87+129=216
We need 432 apples,
216 bottles of water
Bought Apple 5 × 6 × 10 = 300
Water 24 × 9 = 216 bottles
So it's not enough
A and B are 1170km apart, and a and B trains run from a and B for 3 hours at the same time. If the speed ratio of a and B trains is 5; 8, how many lines are there
1107/3=390km/h
390*5/13=150km/h
390*8/13=240km/h
A: 150 * 3 = 450km
B: 240 * 3 = 720km
Root 2 minus 1 / 2 plus root 8 - root 2 plus 1
1/√2-1+√8-√2+1
Root 2 minus 1 / 2 plus root 8 - root 2 plus 1
=1/(√2-1)+√8-√2+1
=(√2+1)/(√2+1)(√2-1)+2√2-√2+1
=√2+1+√2+1
=2√2+2
Root 8 plus 2
Two root two plus two
In the construction site, 1.5 tons of cement and 6 tons of yellow sand are mixed to form cement mortar. The mass ratio of cement and yellow sand in the cement mortar is written and simplified
The quality of cement: the quality of yellow sand, = 1.5:6, = (1.5 △ 1.5): (6 △ 1.5), = 1:4, a: the mass ratio of cement and yellow sand in this cement mortar is 1:4
RELATED INFORMATIONS
- 1. It is known that train a runs 120 kilometers per hour and train B 150 kilometers per hour, It is known that train a runs 120 kilometers per hour and train B 150 kilometers per hour 1. What is the ratio of the time when the two trains meet? 2. What is the ratio of the time taken by a and B trains to complete the whole journey?
- 2. The two trains of Party A and Party B depart from two places 275km apart and meet 2.5 hours later. It is known that the speed of train B is 60km per hour, How many kilometers does car a travel per hour Fang Chengjie
- 3. A and B trains leave from a and B at the same time. After five hours' meeting, the two trains still run at the same speed It takes another 4 hours to drive to B. It is known that car a travels 10 kilometers more per hour than car B. how many kilometers are there between the two places? 2. How many days will it take for the maintenance team to repair 1500 air tanks in 10 days with 30 people? How many days will it take to repair 9000 air tanks with 30 people The first question is not necessary 1. A and B trains leave from a and B at the same time. After 5 hours of meeting, the two trains still drive at the same speed, and then drive to B after 4 hours. It is known that car a travels 10 kilometers more per hour than car B. how many kilometers are there between the two places?
- 4. The distance between station a and station B is 1280 meters. After adopting the "harmony" EMU to increase the speed, the running speed of the train is 3.2 times of the original speed Continued: the time is shortened by 11 hours. How to calculate the speed of the train after speed increase? (equation)
- 5. The two trains of Party A and Party B start from the same city and run in opposite directions. The speed of train a is 36 km / h, and that of train B is 48 km / h. It is known that train a starts 2 hours earlier than train B After how many hours, B catch up with a
- 6. The length of train a and train B are 144 meters and 180 meters respectively, and train a travels 4 meters more per second than train B. (1) it takes 9 seconds for the two trains to travel in opposite directions, from meeting to completely staggering. What's the speed of the two East trains? (2) if they travel in the same direction, how many seconds does it take for the head of train a to catch up with the tail of train B to completely overtake train B?
- 7. The two trains run from two places 450 kilometers apart and meet each other in five hours. It is known that the speed ratio of the two trains is 4:5. How many kilometers do the two trains travel per hour?
- 8. A and B two trains from 450 kilometers away from the two places at the same time, after five hours just met, known a and B two car speed ratio is 4:5, two trains every hour how many kilometers? Tell me why? Good 50 minutes!
- 9. A passenger car and a freight car leave from two places at the same time. When they meet, the passenger car travels 60 kilometers more than the freight car. It is known that the speed of the freight car is four fifths of that of the passenger car. The distance between two places should be calculated
- 10. The distance between a and B is 360 km. A car from a to B runs 108 km in 2 hours. According to this calculation, it will take several hours to complete the whole journey Make no mistake, 108 kilometers in 2 hours
- 11. The two trains leave 500 kilometers apart at the same time, but they don't meet each other four hours later. They are 20 kilometers apart. It is known that car a travels 65 kilometers per hour, and how many kilometers does car B travel per hour?
- 12. A. The distance between city B is 1000 km. The two trains of a and B start from city a and B at the same time and run in opposite directions. They meet on the way. Car a arrives at place B 15 hours after meeting, and car B arrives at place a 6 + 2 / 3 hours after meeting. If the speed of car B is 1.5 times that of car a, the speed of car a and car B should be calculated (set up equations to solve practical problems)
- 13. After 7 hours' meeting, car a is 6 kilometers faster than car B per hour, and the speed is 5; 6. How many kilometers is the distance between two places? Use the equation
- 14. The distance between a and B is 480km. Two cars a and B start from two places at the same time and run in opposite directions. They meet in six hours. It is known that the speed ratio of a and B is 9:7. What is the speed of a and B?
- 15. The two vehicles run from two places 210km apart at the same time. After 8 minutes and 7 hours, they run 75% of the whole journey. It is known that the speed ratio of the two vehicles is 3:1
- 16. A. B is 480 km away from each other. A and B start from a and B respectively, and run in opposite directions. They meet in 2 hours and 30 minutes. It is known that the speed of a is 80 km per hour, and how many km per hour is the speed of B?
- 17. A passenger car and a freight car leave from a and B at the same time. After six hours of meeting, the two trains continue to run at the same speed A passenger car and a freight car leave from a and B at the same time. After six hours of meeting, the two trains continue to move forward at the original speed. The passenger car runs for another four hours to reach B. after meeting, how many hours will it take the freight car to reach a?
- 18. Two trains a and B leave the two cities 1620 kilometers apart at the same time, and meet each other after 6 hours. It is known that car a is 14 times faster than car B per hour. How many kilometers is car B's speed?
- 19. The two cities are 308km apart. The two trains left each other at the same time and met three hours later. It is known that car a is one third faster than car B,
- 20. A and B two trains at the same time from AB two opposite, 10 hours meet Now, four hours after driving from both places, car a stops at C, and car B arrives at C nine hours later. Q: how many hours does it take for car a to go from a to B?