Two hours after the Wenchuan earthquake, an armed police unit set out from XX County for rescue. They left at 1:15 a.m. on the 13th, but they met with trouble on the way. They decided to walk, but they were delayed for an hour because of saving people in Dali County. Then, they sent a detachment to increase the walking speed by 1 / 9. They arrived in Wenchuan at 23:15 on the 13th~ What is the average speed of the advance team from Lixian to Wenchuan? I'll add it! Also ask the time from the beginning to Lixian, the speed and time from Lixian to Wenchuan (this is the table) It's 30 kilometers from Lixian to Wenchuan and 60 kilometers from Lixian to Wenchuan It is the time from XX county to Li County, the speed and time from Li county to Wenchuan What is the average speed of the advance team from Lixian to Wenchuan? ``````````````````````````````````````````````````````````` Dizzy``````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````

Two hours after the Wenchuan earthquake, an armed police unit set out from XX County for rescue. They left at 1:15 a.m. on the 13th, but they met with trouble on the way. They decided to walk, but they were delayed for an hour because of saving people in Dali County. Then, they sent a detachment to increase the walking speed by 1 / 9. They arrived in Wenchuan at 23:15 on the 13th~ What is the average speed of the advance team from Lixian to Wenchuan? I'll add it! Also ask the time from the beginning to Lixian, the speed and time from Lixian to Wenchuan (this is the table) It's 30 kilometers from Lixian to Wenchuan and 60 kilometers from Lixian to Wenchuan It is the time from XX county to Li County, the speed and time from Li county to Wenchuan What is the average speed of the advance team from Lixian to Wenchuan? ``````````````````````````````````````````````````````````` Dizzy``````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````

The average speed from Li to Wenchuan is x km / h
It takes 22 hours, but the walking time t = 22-1 = 21 hours
The equation: (30 / x) + [60 / (x + X / 9)] = 21
Solving the equation: 84 / x = 21
X = 4 km / h
A: the average speed of the advance team from Li to Wenchuan is 4 kilometers per hour