It is given that the tablet is to be taken 2 times a day.
That means in 1 day, 2 tablets will be taken.
So in 90 days the number of tablets is calculated as follows:
[tex]\begin{gathered} 1\text{ day}\Rightarrow2\text{ tablets} \\ 90\times1\text{ day}\Rightarrow90\times2\text{ tablets} \\ 90\text{ days}\Rightarrow180\text{ tablets} \end{gathered}[/tex]Hence Marilyn will take 180 tablets in 90 days.
