[tex]15\ minutes=\frac{15}{60}hour=\frac{1}{4}hour\\\\
\frac{1}{4}h-\frac{1}{5}\ bag\\
1\ hour-\ x\ bag\\\\
cross\ multiplication\\
\frac{1}{4}x=\frac{1}{5}\ \ \ | multiply\ by\ 4\\\\
x=\frac{4}{5}\\\\
Rate\ is\ equal\ to\ \frac{4}{5}\ bag\ per\ 1\ hour.[/tex]