Xiaoming and Xiaogang travel by train. It takes only 2 hours to leave the train. Their home is 12 kilometers away from the station, and they can only walk 4 kilometers per hour on foot. According to this speed, they have to miss the train. Just as Xiaohua passes by by by by bike, he takes Xiaoming for 9 kilometers to walk on, and then returns to the original road to meet Xiaogang. Xiaohua meets Xiaogang 3 kilometers away from their home and takes Xiaogang with him Chase Xiaoming. They arrived at the station ahead of time. Do you know they arrived at the station a few minutes before driving?

Xiaoming and Xiaogang travel by train. It takes only 2 hours to leave the train. Their home is 12 kilometers away from the station, and they can only walk 4 kilometers per hour on foot. According to this speed, they have to miss the train. Just as Xiaohua passes by by by by bike, he takes Xiaoming for 9 kilometers to walk on, and then returns to the original road to meet Xiaogang. Xiaohua meets Xiaogang 3 kilometers away from their home and takes Xiaogang with him Chase Xiaoming. They arrived at the station ahead of time. Do you know they arrived at the station a few minutes before driving?

The time Xiaogang takes to walk 3km is: 3 △ 4 = 34 (hours); the speed of Xiaohua's bicycle is: (9 − 3 + 9) △ 34 = 20 (km / h); the time Xiaoming takes to get to the railway station is: 9 △ 20 + (12-9) △ 4 = 1.2 (hours); the time Xiaogang takes to get to the railway station is: 3 △ 4 + (12-3) △ 20 = 1.2 (hours); the time Xiaoming and Xiaogang arrive at the railway station before driving is: 2-1.2 = 0.8 (hours) A: they arrived at the station 48 minutes before driving

A man walked from his home to the bus station. He walked 3 kilometers in the first hour. He looked at his watch and estimated that he would be 40 minutes late at this speed. Therefore, he walked the rest of the way at the speed of 4 kilometers per hour. Instead, he arrived 45 minutes ahead of time and asked for the distance from the other person to the bus station

Suppose the distance between the person's home and the bus station is x km, then the equation is: x3 − 23 = x − 34 + 34 + 1, and the solution is: x = 20 km. Therefore, the distance between the person's home and the bus station is 20 km

From home to the railway station, you can travel 30 kilometers an hour, 15 minutes early, 15 kilometers an hour, and 15 minutes late. If you want to arrive 5 minutes earlier, what's the speed?

It took X minutes to get there
30*（x-15）=15*（x+15）
The solution is x = 45
So the distance is 15 * 1 = 15km
15 / (45-5) = 22.5km/h