20:2 2/15+25 5/7:1 1/35

20 : 2 2/15 + 25 5/7 : 1 1/35 = 34 целых 3/8

1) 20 : 2 2/15 = 20 : 32/15 = 20/1 * 15/32 = (5*15) / (1*8) = 75/8 = 9 3/8

2) 25 5/7 : 1 1/35 = 180/7 : 36/35 = 180/7 * 35/36 = (5*5) / (1*1) = 25

3) 9 3/8 + 25 = 34 3/8

Пояснения:

2 целых 2/15 = (2*15+2) / 15 = 32/15

25 целых 5/7 = (25*7+5) / 7 = 180/7

1 целая 1/35 = (1*35+1) / 35 = 36/35