4/45 - 1/30 = (4*2)/90 - (1*3)/90= 8/90-3/90= 5/90= 1/18
17/18 -11/12= (17*2)/36 -(11*3)/36 = 34/36 - 33/36 =1/36
3 3/7:(2/7•х)=3 1/3:5/9
3 3/7:(2/7•х)=6
2/7•х=6:3 3/7
2/7•х=1 3/4
х=1 3/4:2/7
х=6 1/8
21/8, 16/9, 129/14, 51/11, 113/18, 83/10 191/14.
1)28*5=140 км весь маршрут
2)140-28=112 км осталось пройти
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