Вычислить: 3 : 15/16 - (5/21 * 7/25 + 1/10)

1. 3 : 15/16 = 3 * 16/15 = 16/5.
2. (5/21 * 7/25 + 1/10) = (1/3 * 1/5 + 1/10) = (1/15 + 1/10) = (2/30 + 3/30) = 5/30 = 1/6.
3. 16/5 - 1/6 = (96 - 5) / 30 = 91/30 = 3 1/30.