ANSWER
[tex]30\text{ balloons}[/tex]EXPLANATION
To find the number of balloons that are purple, we have to find six-sevenths of 35.
That is:
[tex]\begin{gathered} \frac{6}{7}*35 \\ 6*5 \\ 30\text{ balloons} \end{gathered}[/tex]That is the number of balloons that are purple.