well, that week she earned her salary $240 plus 3% of 3500, hmmmm what is 3% of 3500?
[tex]\bf \begin{array}{|c|ll} \cline{1-1} \textit{a\% of b}\\ \cline{1-1} \\ \left( \cfrac{a}{100} \right)\cdot b \\\\ \cline{1-1} \end{array}~\hspace{5em}\stackrel{\textit{3\% of 3500}}{\left( \cfrac{3}{100} \right)3500}\implies 105~\hspace{7em} \begin{array}{|c|ll} \cline{1-1} total~salary\\ \cline{1-1} 240+105\\ 345 \\ \cline{1-1} \end{array}[/tex]
