Two people, A and B, set out from A and B at the same time and walked towards each other. B's speed is two-thirds that of A. After they meet, they move on. When A arrives at B, B returns immediately. It is known that the place where they met for the second time is 3000 meters away from the place where they met for the first time. How to find the distance between a and b?

2. A car goes from A to B. If you reduce the speed by 10%, you will arrive 1 hour later than the original time. If you drive at the original speed of 1 80km and increase the speed by 20%, you will arrive1hour earlier than the original time. What is the distance between a and b?

Xiaoming walks from home to school in the morning. When he ran halfway, his father found that Xiao Ming's math book was left at home, and then he rode to deliver it to Xiao Ming. When catching up, Xiao Ming still had a long way to go, so he got on his father's car and was sent to school by his father, so Xiao Ming arrived at school five minutes earlier than walking alone. How long does it take Xiaoming to walk from home to school?

4. Lele needs to walk home from school 14 points, Jingjing needs to walk home from school 14 points. It is known that Jingjing travels more home than Lele, and Lele walks 12 meters more than Jingjing every minute. How many meters is Jingjing's journey home?