The fast and slow trains run from AB to ab at the same time. After 4 hours, they meet at 18 kilometers away from the destination. It is known that the fast train runs 70 kilometers per hour

The fast and slow trains run from AB to ab at the same time. After 4 hours, they meet at 18 kilometers away from the destination. It is known that the fast train runs 70 kilometers per hour

Let's meet in four hours at 18 kilometers from the midpoint
Set the local train to travel x kilometers per hour
4（70-X）=18*2
X=61
The local train runs 61 kilometers per hour

It is known that the local train travels 40 kilometers per hour. After three hours, the local train meets the express train 12 kilometers away from the destination,
How many kilometers per hour does the express run? It's urgent,

The topic should be: after three hours of slow train, we meet the express train at 12 kilometers from the midpoint. Right?
40 + 12 × 2 △ 3 = 48 (km)
A: the express runs 48 kilometers per hour

A local train and an express train leave from station a and station B at the same time. After 20 hours of meeting, it will take 30 hours for the local train to reach station B, and how many hours for the express train to reach station a?

20 + 30 = 50 (hours) 1 ^ [(1-2050) ^ 20] - 20 = 1 ^ [3050 ^ 20] - 20 = 1 ^ 3100-20 = 3313-20 = 1313 (hours) a: it will take 1313 hours for the express train to reach station a