Решите выражение \( \left( \frac{5}{12} + 1 \frac{1}{3} \right) \cdot 3 \).

\[ \left( \frac{5}{12} + 1 \frac{1}{3} \right) \cdot 3 = \left( \frac{5}{12} + \frac{4}{3} \right) \cdot 3 = \left( \frac{5}{12} + \frac{16}{12} \right) \cdot 3 = \frac{21}{12} \cdot 3 = \frac{63}{12} = \frac{21}{4} = 5 \frac{1}{4}. \] Ответ: \( 5 \frac{1}{4} \).