Answer
$45.\overline{45}\ drops/min$
Work Step by Step
Flow rate is expressed as drops per minute. Use conversion factors (equal ratios) to convert the given values.
$\frac{1\ L}{5.5\ hr}=\frac{1\ L}{5.5\ hr}\times\frac{1000\ mL}{1\ L}\times\frac{15\ drops}{1\ mL}\times\frac{1\ hr}{60\ min}=\frac{15000\ drops}{330\ min}=\frac{15000\div330\ drops}{330\div330\ min}=\frac{45.\overline{45}\ drops}{1\ min}$