From the double number line, we can see that the corresponding number of Green and Purple beads needed in each case are stated.
[tex]\begin{gathered} 4\text{ Gre}en\text{ }\rightarrow5\text{ Purple} \\ 8\text{ Gr}een\text{ }\rightarrow10\text{ Purple} \\ \cdot \\ \cdot \\ 20\text{ Gre}en\text{ }\rightarrow\text{ 25 Purple} \end{gathered}[/tex]
Therefore, for 20 Green beads she will need to use 25 Purple Beads.
[tex]25\text{ Purple Beads}[/tex]
