Given:
Lucy needs to memorize words on a vocabulary list for Korean class.
Let the number of words on the list = x
She has memorized 20 of the words, which is four-fifths of the list.
So, we can write the following equation:
[tex]\frac{4}{5}x=20[/tex]Solve the equation for (x), multiply both sides by 5/4
[tex]\begin{gathered} \frac{5}{4}*\frac{4}{5}x=\frac{5}{4}*20 \\ \\ x=\frac{100}{4}=25 \end{gathered}[/tex]So, the answer will be:
The number of words on the list = 25
