\[\frac{5 - y}{4} = \frac{3}{7}\]
\[5 - y = \frac{3 \cdot 4}{7}\]
\[y = 5 - \frac{12}{7} = \frac{35 - 12}{7} = \frac{23}{7}\]
\[y = 3\frac{2}{7}.\]