一道计算题 0.2[5/6除以（0.15+20/9）]

0.2[5/6除以（0.15+20/9）]
=0.2*[5/6÷427/180]
=1/5*5/6*180/427(约分)
=30/427

如果是0.15+9/20的话
0.2[5/6除以（0.15+9/20）]
=0.2*[5/6÷3/5]
=1/5*5/6*5/3(约分)
=5/18

全部化为分数
(1/5)/[(5/6)/(3/20+20/9)]
=(1/5)/[(5/6)/(27/180+400/180)]
=(1/5)/[(5/6)/(427/180)]
=(1/5)/[(5/6)*(180/427)]
=(1/5)/(150/427)
=(1/5)*(427/150)
=427/750

0.15=3/2
3/2+20/9=310/18
5/6除以310/18
即5/6*18/310=275/54