9/55
Пошаговое объяснение:
4 2/5 * 15/77 * 7/20 = 12/5 * 15/77 * 7/20 = 9/55
1. 12/5 * 15/77 = 36/77
2. 36/77 * 7/20 = (36*7)/(77*20) = 9/55
