ANSWER
100 plates
EXPLANATION
We have that the roll of foil has 25 yards of foil.
Lori sets 5 yards of foil aside.
This means that the amount of foil left is now:
[tex]\begin{gathered} 25-5 \\ 20\text{ yards} \end{gathered}[/tex]She covers plates with the rest (20 yards) of the foil and each plate requires 1/5 yard.
To find the number of plates she was able to cover, we have to divide the total amount of foil by the amount of foil that each plate requires.
That is:
[tex]\begin{gathered} \frac{20}{\frac{1}{5}} \\ =20\div\frac{1}{5} \\ =20\cdot5 \\ =100\text{ plates} \end{gathered}[/tex]She was able to cover 100 plates.
