Question

To find a discount of 15% off of a price of B, which expression should you use to find the final price?

Answer 1

so the original price was B, which is the 100%, but today is on sale and is 15% off, that means the sale price must be 100% - 15% = 85%, well

`\begin{array} \cline{1-1} \textit{\textit{\LARGE a}\% of \textit{\LARGE b}}\\ \cline{1-1} \\ \left( \cfrac{\textit{\LARGE a}}{100} \right)\cdot \textit{\LARGE b} \\\\ \cline{1-1} \end{array}~\hspace{5em}\stackrel{\textit{85\% of B}}{\left( \cfrac{85}{100} \right)B}\implies {\Large \begin{array}{llll} 0.85B \end{array}}`