99/160:33/40*20/27:5/81
1)99/160:33/40=99*40/160*33=3/4
2) 3/4*20/27=3*20/4*27=60/108=30/54=15/27=5/9
3) 5/9:5/81=5*81/5*9=9
ответ 9
