4) (1 1/2 + 2 2/3 + 3 3/4) * 3 3/5 / (14 - 15 1/8 : 2 1/5)

1. Convert mixed numbers to improper fractions: (3/2 + 8/3 + 15/4) * 18/5 / (14 - 121/8 : 11/5).
2. Perform addition in the numerator: (18/12 + 32/12 + 45/12) = 95/12.
3. Perform division in the denominator: 14 - (121/8 * 5/11) = 14 - 55/8 = (112/8 - 55/8) = 57/8.
4. Perform multiplication and division: (95/12 * 18/5) / (57/8) = (57/2) / (57/8) = 57/2 * 8/57 = 4.