A and B ride each other and meet each other in 8 hours. If a travels less than 1 km per hour and B travels more than 3 km per hour, they will meet each other in 7 hours Please don't use XY to solve problems, the teacher hasn't taught yet

A and B ride each other and meet each other in 8 hours. If a travels less than 1 km per hour and B travels more than 3 km per hour, they will meet each other in 7 hours Please don't use XY to solve problems, the teacher hasn't taught yet

It used to be 1 / 8 of the whole journey per hour, but now it is 1 / 7 of the whole journey per hour
Now one hour is 3-1 = 2km more than before
Therefore, the whole distance = 2 / (1 / 7-1 / 8) = 112 km

Party A and Party B drive from the East and the west at the same time and meet in 8 hours. If Party A travels less than 1 kilometer per hour and more than 3 kilometers per hour, they can meet after 7 hours. How many kilometers are there between the East and the west? "

Let's make the equation~
Let a velocity x km / h and B be y
8(x+y)=7(x-1+y+3)
The solution is x + y = 14
So the distance is 8 * 14 = 112 (km)
Another explanation is that the speed and speed of the two people in the second time are increased by 2km / h, so the 7-hour journey is 14km more than that in the first time, that is, 14km in the last hour of the first time, so the total distance is 14 * 8 = 112km

Party A and Party B walk back from point a at the same time and walk along the 400 meter circular runway. Party A walks 80 meters per minute and Party B walks 50 meters per minute. How many minutes do they need to meet at point a
Party A and Party B walk back from point a at the same time and walk along the 400 meter circular runway. Party A walks 80 meters per minute and Party B walks 50 meters per minute. How many minutes will it take at least for them to meet at point a?

A 5 minutes, B 8 minutes
Meeting at point a 5 * 8 = 40 minutes

A and B walk around the 400 meter circular runway at the same time. If they walk from the same starting point and back at the same time, they can meet in 2.5 minutes. If they walk from the same point and direction at the same time, a can catch up with B in 12.5 minutes?

Speed sum of a and B: 400 △ 2.5 = 160 (m), speed difference between a and B: 400 △ 12.5 = 32 (m), speed of a: (160 + 32) △ 2, = 192 △ 2, = 96 (m), speed of B: 160-96 = 64 (M); answer: a walks 96 meters per minute, B walks 64 meters per minute