Пошаговое объяснение:

№5

27 : 9/11 = 27 * 11/9 = 3 * 11/1 = 33/1 = 33 (км) - должна проплыть всего лодка

№6

1)

х : 13/18 = 9/26

х = 9/26 * 13/18

х = 1/2 * 1/2

х = 1/4

2)

3 3/5 : х = 2 1/4

х = 3 3/5 : 2 1/4

х = 18/5 : 9/4

х = 18/5 * 4/9

х = 2/5 * 4/1

х = 8/5

х = 1 3/5

№8

1) 6,75 + 2 1/6 = 6 75/100 + 2 1/6 = 6 3/4 + 2 1/6 = 6 9/12 + 2 2/12 = 8 11/12

2) 8 11/12 - 3,5 = 8 11/12 - 3 5/10 = 8 11/12 - 3 1/2 = 8 11/12 - 3 6/12 = 5 5/12

3) 5 5/12 : 2 3/5 = 65/12 : 13/5 = 65/12 * 5/13 = 5/12 * 5/1 = 25/12 = 2 1/12

4) 1 1/3 : 8/9 = 4/3 * 9/8 = 1/1 * 3/2 = 3/2 = 1 1/2

5) 2 1/12 - 1 1/2 = 2 1/12 - 1 6/12 = 1 13/12 - 1 6/12 = 7/12