If the speed of the green team is 10x and the speed of the red team is 9x, it will become 9x( 1+20%) after acceleration, and the remaining 1000km will be given to the green team and 1200km to the red team. The time for the Green Team to arrive in Beijing is 1000/ 10x =
The time for the Red Team to arrive in Beijing is1200/9x (1+20%) =1000/9x.
The time is not equal, so they won't arrive at the same time.
Because team B takes a long time, when team A arrives at team A first, team B still has1200-100/x9x (1+20%) =120km left.