0.25*(1+40%)=0.35
卖出1200x80%=960
设折扣是x
0.35x960+0.35(1200-960)x-0.25x1200=1200x0.25x40%x86%
336+84x-300=103.2
36+84x=103.2
84x=103.2-36
84x=67.2
x=0.8
答:打8折
0.25*(1+40%)=0.35
卖出1200x80%=960
设折扣是x
0.35x960+0.35(1200-960)x-0.25x1200=1200x0.25x40%x86%
336+84x-300=103.2
36+84x=103.2
84x=103.2-36
84x=67.2
x=0.8
答:打8折