Flight Guangzhou Baiyun International Airport departs from Guangzhou Guangzhou Baiyun International Airport at 17:20 and arrives at Seoul Incheon International Airport at 21:45.
The flighttime is about 3h 25m. The distance travelled ("as the bird flies"): 1648 Km. So the average speed is roughly 482 Km.
There is an 1 hour time difference between Guangzhou and Seoul