Answer:
175 mg/day
Step-by-step explanation:
It's a matter of units conversion. The conversion factors all have a value of 1 (the numerator is equal to the denominator), and all are chosen to cancel units you don't want and give units you do want.
[tex]\dfrac{47\,ml}{6\,h}\cdot\dfrac{24\,h}{1\,day}\cdot\cfrac{28\,mg}{30\,ml}=\dfrac{47\cdot 24\cdot 28\,mg}{6\cdot 30\,day}\approx 175\,\text{mg/day}[/tex]
