Решите уравнение: a:1 7/50 =5/57:1/2.

\[a\ :1\frac{7}{50} = \frac{5}{57}\ :\frac{1}{2}\]

\[a = \frac{5 \cdot 2 \cdot 57}{57 \cdot 1 \cdot 50}\]

\[a = \frac{1}{5}.\]