\( 1 \frac{1}{2} = \frac{3}{2} \)
\( 1 \frac{1}{4} = \frac{5}{4} \)
\( 3 : \frac{3}{2} + 5 : \frac{5}{4} \)
\( 3 : \frac{3}{2} = 3 \cdot \frac{2}{3} = 2 \)
\( 5 : \frac{5}{4} = 5 \cdot \frac{4}{5} = 4 \)
\( 2 + 4 = 6 \)
Ответ: 6