Answer
It takes $~62.5~s~$ for the medicine to travel throughout the body.
Work Step by Step
We can convert $5~L$ to units of $m^3$:
$5~L \times \frac{10^{-3}~m^3}{1~L} = 5\times 10^{-3}~m^3$
We can find the time for the medicine to travel throughout the body:
$t = \frac{5\times 10^{-3}~m^3}{80\times 10^{-6}~m^3/s}$
$t = 62.5~s$
It takes $~62.5~s~$ for the medicine to travel throughout the body.
