1.设有X个人,甲旅行社总的费用为Y1,乙旅行社总的费用为Y2
当Y1>Y2时,
0.75×200X>0.8×200(X-1)
150X>160X-160
Xx
x/2-x>1
-x/2>1
x5x
ax-5x>6
(a-5)x>6
x8a
3a