Given the coefficient of correlation and coefficient of determination relationship as
[tex]\text{ coefficient of }\det \text{ermintaion}=r^2[/tex]Since,
[tex]r=0.642[/tex]Then,
[tex]\begin{gathered} \text{ Coefficient of determination=0.642}^2 \\ =0.4122 \end{gathered}[/tex]Thus, the percentage of variation will be;
[tex]\begin{gathered} 0.4122\times100\text{ \%} \\ \Rightarrow41.22\text{ \%} \end{gathered}[/tex]Hence, the percent of the variation in the number of bags of trash collected can be explained by differences in the number of volunteers is 41.22 %