It takes 15 minutes for Xiaoming to go to Xiaojun's house, and it takes 20 minutes for Xiaojun to go to Xiaoming's house. They set out from their own home at the same time, and then they meet in a few minutes

It takes 15 minutes for Xiaoming to go to Xiaojun's house, and it takes 20 minutes for Xiaojun to go to Xiaoming's house. They set out from their own home at the same time, and then they meet in a few minutes

60╱7

The road between Xiaoming and Xiaoliang's home is 2400 meters long. If they start from home at the same time and ride bicycles to each other for 10 minutes, they will meet each other. If the average person walks less than 20 meters per minute, the distance between the second meeting place and the first meeting place is 20 meters. How many meters does the fast cyclist walk per minute?
Why did the second walk 20 meters more than the first?

For the first time, the speed sum of the two was 2400 / 10 = 240 (M / min)
The second time they met was 2400 / (240-20 * 2) = 12 (minutes)
Because the time of the second encounter is long and the speed difference between two people is fixed, the person with high speed will walk more in the second time than in the first time. If the speed of the first time is x m / min, then
12(x-20)-10x = 20
The solution is x = 130
That is, the average speed of fast cyclists is 130 m / min for the first time and 110 m / min for the second time

Xiaoming's speed is 2 / 3 of Xiaojun's. they start from a and B respectively. If they go in opposite directions, they will meet one hour later. If they go in the same direction, Xiaojun will catch up with Xiaoming more
How long?

1×2/（3+2）=2/5
1-2/5=3/5
1 ÷ (3 / 5-2 / 5) = 5 hours