Пошаговое объяснение:
1) 5/7 : 2/3 = 5/7 * 3/2 = 15/14
2) 15/14 * 9/30 = 1/14 * 9/2 = 9/28
3) 9/14 * 1/6 = 3/14 * 1/2 = 3/28
4) 9/28 : 3/28 = 9/28 * 28/3 = 9/3 = 3
5) 3 * 1. 1/3 = 3 * 4/3 = 12/3 = 4
ответ: 4
