（0.8x0.4+0.8x0.2十0.4x0.2)x2=（0.8x0.4+0.8x0.2十0.8x0.1)x2=0.8x（0.4+0.2+0.1)x2=0.8*0.7*2=1.12
0.8×（0.4+0.2+1）×2=1.6×1.6=2.56
等于1.12
9.2
