A travel agency: a+a+0.5a = 2.5a.
Travel agency: (a+a+a) * 0.8 = 2.4a.
Because 2.5a >: 2.4a
So a charges more.
Height 2.5a-2.4a=0. 1a
If a=600
Then:
B =2.4*600= 1440 (yuan)
I wonder if I can see it clearly.