Answer
5 hr
Work Step by Step
First determine the total number of drops to be administered.
$500\ mL\times\frac{15\ drops}{mL}=7500\ drops$
Divide the number of drops by the flow rate to find the time.
$7500\ drops\div\frac{25\ drops}{1\ min}=7500\ drops\times\frac{1\ min}{25\ drops}=300\ min$
$300\ min\times\frac{1\ hr}{60\ min}=5\ hr$
