题目

(0.1*0.3*0.9+0.2*0.6*1.8+0.3*0.9*2.9)除以（0.1*0.2*0.4+0.2*0.4*0.8+0.3*0.6*1.2）

提问时间：2020-07-25

答案

(0.1×0.3×0.9+0.2×0.6×1.8+0.3×0.9×2.9) / (0.1×0.2×0.4+0.2×0.4×0.8+0.3×0.6×1.2)
=(1×3×9+2×6×18+3×9×29) / (1×2×4+2×4×8+3×6×12)
=27×(1+8+29) / [8×(1+8+27)
=27×38 / (8×36)
=3×19 / (4×4)
=57 / 16