设:A至少打x折消费者买才合算
365*10*0.4+2190x=365*10*0.4*0.55+2190*(1+10%)
365*4*(1-0.55)=2190*(1.1-x)
4*0.45=6*(1.1-x)=6.6-6x
6x=6.6-1.8=4.8
x=0.8=80%
所以:A至少打8折消费者买才合算
设:A至少打x折消费者买才合算
365*10*0.4+2190x=365*10*0.4*0.55+2190*(1+10%)
365*4*(1-0.55)=2190*(1.1-x)
4*0.45=6*(1.1-x)=6.6-6x
6x=6.6-1.8=4.8
x=0.8=80%
所以:A至少打8折消费者买才合算