1, A car and B car leave from AB at the same time. A walked 5/ 1 1 of the whole journey. If A drives at a speed of 4.5 kilometers per hour, B drives for 5 hours. How many kilometers are AB apart?

Solution: AB distance = (4.5× 5)/(5/11) = 49.5 km.

2. A bus and a truck leave from Party A and Party B at the same time. The speed of a truck is four-fifths that of a bus. After a quarter of the journey, the truck and the bus met for 28 kilometers. How many kilometers is it between A and B?

Solution: The speed ratio of passenger cars and trucks is 5: 4.

Then the distance ratio when meeting is 5: 4.

When they met, it was 4/9 of the whole truck journey.

At this time, the truck has traveled all the way 1/4.

4/9- 1/4=7/36 from the meeting point.

Then the whole journey = 28/(7/36) = 144km.

3. Party A and Party B walk around the city, with Party A walking 8 kilometers per hour and Party B walking 6 kilometers per hour. Now both of them start from the same place at the same time. After B meets A, it will take another 4 hours to return to the original starting point. B How long does it take to go around the city?

Solution: The speed ratio of A and B = 8: 6 = 4: 3.

When they met, B walked 3/7 of the way.

Then 4 hours is 4/7 of the whole trip.

Therefore, the time spent on line B in a week =4/(4/7)=7 hours.

4. Party A and Party B walk from place A to place B at the same time. When Party A completes the whole journey of 1\4, Party B is still 640 meters away from B. When Party A completes the remaining 5\6, Party B completes the whole journey of 7\ 10. What's the distance between AB and place?

Solution: After A left 1/4, the remaining 1- 1/4=3/4.

Then the remaining 5/6 is 3/4×5/6=5/8.

At this time, a * * * left 1/4+5/8=7/8.

Then the distance ratio between Party A and Party B is 7/8: 7/ 10 = 5: 4.

So when A goes 1/4, B goes 1/4×4/5= 1/5.

Then AB distance =640/( 1- 1/5)=800 meters.

5. Two cars, A and B, start from A and B at the same time and drive in opposite directions. Car A travels 75 kilometers per hour, and car B takes 7 hours to complete the journey. Three hours after the departure of the two cars, the distance is15km. What is the distance between a and b?

Solution: Case A: Party A and Party B have not met yet.

3/7 of the 3-hour journey of the B train.

The three-hour journey is 75×3 = 225 kilometers.

AB distance = (225+15)/(1-3/7) = 240/(4/7) = 420km.

In one case, Party A and Party B have met.

(225- 15)/( 1-3/7)= 2 10/(4/7)= 367.5km。

6. One, two people should go this way. A It takes 30 minutes to walk and 20 minutes to walk. After walking for 3 minutes, A found that she didn't take anything, which delayed for 3 minutes. How many minutes does it take to walk from A to B?

Solution: A is 3+3+3=9 minutes later than B.

Think of the whole distance as 1.

Then the speed of a = 1/30.

Speed B = 1/20

When Party A packed up and set out, Party B had already left 1/20×9=9/20.

Then the distance between Party A and Party B is1-9/20 =11/20.

The sum of the speeds of Party A and Party B =1/20+1/30 =112.

Then meet again in (11/20)/(112) = 6.6 minutes.

7. two cars, a and b, start from place a and drive in the same direction. A walks 36 kilometers per hour and B walks 48 kilometers per hour. If car A leaves two hours earlier than car B, how long will it take for car B to catch up with car A?

Solution: distance difference = 36× 2 = 72km.

Speed difference = 48-36 = 12km/h

It takes 72/ 12=6 hours for car b to catch up with car a.

8. Party A and Party B respectively set out from ab, which is 36 kilometers apart, and walked in opposite directions. When Party A departs from A to 1 km, it has been in A until it finds something and returns immediately. After the goods were gone, he immediately went from place A to place B, where Party A and Party B met. He knew that Party A walked 0.5 kilometers more than Party B every hour and asked both of them to walk.

Solution:

A actually walked 36× 1/2+ 1× 2 = 20km when they met.

B walked 36× 1/2 = 18km.

Then A walked 20- 18 = 2km more than B.

Then the meeting time =2/0.5=4 hours.

So A = 20/4 speed = 5 km/h.

Speed B = 5-0.5 = 4.5km/h/h.

9. At the same time, two trains travel in opposite directions from two places 400 kilometers apart. The bus speed is 60 kilometers per hour, and the truck speed is 40 kilometers per hour. A few hours later, did the two trains meet at 100 km?

Solution: velocity sum = 60+40 =100 km/h.

There are two situations,

No encounter

Then the required time =(400- 100)/ 100=3 hours.

Met it.

Then the required time =(400+ 100)/ 100=5 hours.

10, A travels 9 kilometers per hour, and B travels 7 kilometers per hour. They walked back to back at the same time in two places 6 kilometers apart, and a few hours later they were separated by 150 kilometers.

Solution: velocity sum = 9+7 =16 km/h.

Then after (150-6)/16 =144/16 = 9 hours, the distance is150 kilometers.

1 1. Two cars A and B are driving in opposite directions at the same time from two places 600 kilometers apart. It is known that car A travels 42 kilometers per hour and car B travels 58 kilometers per hour. How many kilometers did B car travel when they met?

Solution:

Speed sum =42+58= 100 km/h

Meeting time =600/ 100=6 hours.

When they met, B traveled 58×6= 148 km.

or

The speed ratio of car A and car B = 42: 58 = 2 1: 29.

So when we met, B traveled 600×29/(2 1+29)=348 kilometers.

12, the two cars are facing each other, and meet in six hours. Four hours later, the bus arrived, and the van was still 188 kilometers away. How far is the distance between the two places?

Solution: treat the two cars as a whole.

65438+ 0/6 of the whole journey of two cars per hour

4 hour line 1/6×4=2/3

Then the whole journey =188/(1-2/3) =188× 3 = 564 km.

13. The distance between Party A and Party B is 600 kilometers. The bus and truck traveled in opposite directions from two places and met for six hours. As we all know, the speed of a truck is two-thirds that of a bus. What is the speed of the two cars?

Solution: the sum of the speeds of two cars = 600/6 =100 km/h.

Bus speed =100/(1+2/3) =100× 3/5 = 60 km/h.

Freight car speed = 100-60 = 40km/h

14. The rabbit and the kitten walked in opposite directions from A and B, which are 40 kilometers apart, respectively. Four hours later, they met for four kilometers. How long did it take to meet again?

Solution: velocity sum = (40-4)/4 = 9 km/h.

Then it will take 4/9 hours to meet.

15, car a and car b leave from a and b respectively. Car A travels 50 kilometers per hour and car B travels 40 kilometers per hour. Train A is earlier than train B 1 hour. What's the distance between the two places?

When car A reaches the finish line, car B is 40× 1 = 40km away from the finish line.

Car a travels 40 kilometers more than car B.

Then the time for a car to reach the finish line is 40/(50-40) = 4 hours.

Distance between the two places = 40× 5 = 200km.

16. Two cars leave from Party A and Party B at the same time and meet at 4 o'clock. The speed of the local train is three-fifths of that of the express train. When we met, the express train traveled 80 kilometers more than the local train. How far is the distance between the two places?

Solution: The speed ratio of the express train and the local train = 1: 3/5 = 5: 3.

When they met, the express train traveled 5/8 of the whole journey.

The local train covered three-eighths of the whole journey.

Then the whole journey = 80/(5/8-3/8) = 320km.

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