Who has the circumference question exercise in the itinerary question

The circumference of a circular playground track is 1,200 meters, and two students walk opposite each other at the same time and in the same place.

62 meters in an hour, 58 meters per minute, and the two meet in a few minutes?

Idea pointing: The distance taken by the two people is the circumference of the circular playground track, the speed of the two is mostly known, and the speed can be found, and the time of the encounter with the formula distance and speed can be found to find the time of the encounter.

62 58 120 (m).

1200 120 10 (min).

A: The two met 12 minutes later.

The circumference of the circular track is 800 meters, and two athletes, A and B, start clockwise from the starting point at the same time, the speed of A is 400 meters per minute, and the speed of B is 375 meters per minute, how many minutes later do the two meet for the first time? How many meters did athletes A and B run? How many laps did athletes A and B run?

Ideas: On the circular runway, this is a closed route on the chase problem, the fast should run one more lap than the slow one, the circumference of the circular runway is the chase distance, the speed of the two people is known, and the time of chasing is the time when the two meet.

400 375 25 (m) 800 25 32 (min).

A: 400 32 12800 (m) B: 375 32 12000 (m).

A: 12800 800 16 (circle) B: 16 1 15 (circle).

Exercise: There is a 200-meter-long circular track in Xingfu Village Primary School, Dongdong and Jingjing start from the starting line at the same time, Dongdong runs 6 meters per second, Jingjing runs 4 meters per second, ask Dongdong how many meters each ran when they caught up with Jingjing for the first time, and how many laps did they each run when they caught up with Jingjing for the second time?

The first time Dongdong caught up with Jingjing, he should have traveled 6 100 600 (meters).

The distance traveled when Jingjing was first overtaken: 4 100 400 (meters).

The number of laps that Dongdong ran when he caught up with Jingjing for the second time: (600 2) 200 6 (laps).

Number of laps run by Jingjing when she was caught up for the second time: (400 2) 200 4 (laps).

Summary: The key to answering the problem of chasing on the closed route is to grasp the length of the distance from parallel to the next one.

Summary. It shows that an "old-fashioned" traffic circle is being transformed into a "modern" roundabout: you can see the huge diameter of the old and new roundabouts:

The capacity is the same! In fact, roundabouts are now better thanks to "sliding lanes". In addition, due to the lower speed of vehicles entering the roundabout, the new layout is safe, and what is most important is that due to the vehicle roundabout right of way in all other vehicles, the roundroad is never congested.

Itinerary problem, walking in the same direction along the ring road, why the distance taken by the two after meeting is subtracted to the circumference of the circle.

Itinerary problem, after meeting in the same direction along the ring road, the distance traveled by the two people is subtracted to the circumference of the circle.

It's because of the ferrule.

You're running in the same direction as a person.

The next time he catches up with you, he's pulling you around.

It shows that an "old-fashioned" traffic circle is being transformed into a "modern source" roundabout: you can see the huge diameter of the old and new roundabouts: the traffic capacity is the same!

In fact, thanks to the "sliding lanes", the roundabouts that are now cracked are better. In addition, due to the lower speed of vehicles entering the roundabout, the new layout is safe, and what is most important is that due to the vehicle roundabout right of way in all other vehicles, the roundroad is never congested.

A can run a lap around a circular track in 40 seconds, B runs in the opposite direction at the same time, and meets A every 15 seconds. A can run one lap around a circular runway in 40 seconds, then: A runs 1 40 laps per second; Let it take X seconds for B to complete a lap, then:

B runs 1 x lap per second. If two people run in opposite directions and meet A every 15 seconds, then the distance A and B run together every 15 seconds is 1 lap. So:

1 40)+(1 x)]*15=1 solution: x=24 seconds.

From the first encounter between A and B to the second encounter between A and B, the sum of the distance of A and B is 1 circumference.

The sum of the speed of A and B per minute is: 700 (5 4 + 15 4) = 140 meters A speed per minute: 140 (1 + 2 3) = 84 meters A and B from the departure to the first encounter, the time:

700 140 = 5 minutes then the time taken by A C from departure to the first encounter: 5 + 5 4 = 25 4 minutes A C speed per minute and, is: 700 25 4 = 112 m C speed per minute:

112-84 = 28 meters.

Let the speed of A be x, then the speed of B is 2 3x, and the speed of C is y, then when A and B meet from the first encounter to the second encounter: 5 4 + 15 4 = 5 minutes, the speed of A and B can be found: 5x+5*2 3*x=700, x=84, 2 3x=56

The time it takes for A and C to meet: 5+5 4=25 4 minutes.

25/4*84+25/4*y=700

Find B velocity: y=28

The sum of the distance of A and B is 2 circumferences.

The sum of the speed of A and B per minute is: 700 2 (5 4 + 15 4) = 280 meters A speed per minute: 280 (1 + 2 3) = 168 meters A and B from the start to the first encounter, the time:

700 280 = 5 2 minutes then the time taken by A C from departure to the first encounter: 5 2 + 5 4 = 15 4 minutes A C speed per minute and, is: 700 15 4 = 560 3 meters C speed per minute:

560 3-168 = 56 3 meters.

After another 10 minutes, the two met again, indicating that AB was 2 minutes apart, and the sum of the speed of A and B! ab occupies 2 10 = 1 5

8+6) (1-1 5) = minutes.

I don't know if it's right to understand, but we meet in 8 minutes from the start, A to B in 14 minutes, and meet again in 24 minutes, is that what it means?

Let the runway length be "1", the sum of the speed of A and B is 1 16, and the speed ratio is 4:3, so the speed of A is 1 16 4 7 = 1 28,; 1 1 28 = 28 minutes.

I don't know, I really don't know.

The time for the dog to run is equal to the time it takes for Honghong and Lanlan to meet

36 (4+5) = 4 hours.

The dog ran: 8 4 = 32 km.

Blue butterflies fly lightly, hello:

Analysis: The time when the two meet is the time of the dog's walk.

The time of the encounter is:

36 (4+5) = 4 hours.

The hounds walked together:

4 8 32 (km).

The time when the dog walks is the time when Honghong and Lan Lan meet.

Encounter time 36 9=4

The dog walked 32 kilometers.

The shared time from the turtle to the finish line is 1500 25 = 60 minutes, and the distance of the rabbit run is 1500-200 = 1300 meters.

The time for the rabbit to run is 1300 325 = 4 minutes.

The rabbit sleeps for 60-4 = 56 minutes.

The ratio of distance between A and B is 3:2

The speed ratio between the two after meeting is [3 (1+20%)]2 (1+30%)]18:13

Now B is out of aland.

Then the whole journey is 14 14 45 = 45 km.

When they first met, the distance ratio of A and B was 3:2

Then A has 3 5 for the whole journey, and B has 2 5 for the whole journey

The speed ratio between the two after meeting is [3 (1+20%)]2 (1+30%)]18:13

Then when A arrives at B, the travel ratio of A and B is 18:13

A has 2 5, then B has 2 5 18 13 = 13 45, and B is away from A.

Then the whole journey is 14 14 45 = 45 km.

When they first met, A walked 3 5 and B 2 5, and after the encounter, A's speed was: 3 (1+20%)=, and B's speed was: 2 (1+30%)=

Then when A arrives at B, B's journey is the distance traveled by A: =13 18

At this time, A has 2 5, then the distance of B is 13 45: 2 5 13 18 = 13 45 of line A, that is, 13 45 of the whole process of line B, which is the key to solving the problem, which is transformed into the whole process as a unit "1", and the corresponding score of 14 kilometers is: 3 5 - 13 45 = 14 45, the whole process:

14 14 45 = 45 (km).