Question

Isabella's dance classes 45 minutes long 20% of the time is spent stretching how many minutes does Isabella's spend stretching

Answer 1

$\begin{array}{|c|ll} \cline{1-1} \textit{a\% of b}\\ \cline{1-1} \\ \left( \cfrac{a}{100} \right)\cdot b \\\\ \cline{1-1} \end{array}~\hspace{5em}\stackrel{\textit{20\% of 45}}{\left( \cfrac{20}{100} \right)45}\implies 9$