## Elementary Technical Mathematics

$6.\overline6\ hr$
Find the total number of drops. $1600\ mL\times\frac{10\ drops}{1\ mL}=16000\ drops$ Divide the number of drops by the flow rate to find the time. $16000\ drops\div\frac{40/ drops}{1\ min}=16000\ drops\times\frac{1\ min}{40\ drops}=400\ min$ Convert to hours. $400\ min=400\ min\times\frac{1\ hr}{60\ min}=6.\overline6\ hr$