Given that the number represented by point a on the number axis is 10, the distance between B and a is 5 unit lengths, the number represented by C on the number axis is - 15, and a moves to the right at the speed of 2 unit lengths per second, and point C moves to the right at the speed of 3 unit lengths per second. If a and C start at the same time, how many seconds after a just moves to the end of BC?

Given that the number represented by point a on the number axis is 10, the distance between B and a is 5 unit lengths, the number represented by C on the number axis is - 15, and a moves to the right at the speed of 2 unit lengths per second, and point C moves to the right at the speed of 3 unit lengths per second. If a and C start at the same time, how many seconds after a just moves to the end of BC?

First of all, draw a diagram yourself
There are two cases of B's position, one is 5 and the other is 15
But when B is 5, it needs to satisfy (5 + │ - 15 + 3T │) / 2 = 10 + 2T, but t has no solution
When B is 15, it needs to satisfy (15 + │ - 15 + 3T │) / 2 = 10 + 2T, then t = 10 / 7
Or (15-15 + 3T) / 2 = 10 + 2T, then t has no solution
This is my understanding. I don't know if it is a positive solution. You can analyze it yourself