13/30 : 11/20 * 9/5

1. Делим: (13/30) * (20/11) = (13 * 20) / (30 * 11) = (13 * 2) / (3 * 11) = 26/33.

2. Умножаем: (26/33) * (9/5) = (26 * 9) / (33 * 5) = (26 * 3) / (11 * 5) = 78/55.