Question

Nicole has a loyalty card good for a 18% discount at her local pharmacy. What

number should she multiply the prices on the tags by to find the price she would have
to pay, before tax, in one step?

Answer 1

so let's say the sale price is "P", so Nicole would want to know how much will it be P discounted by 18% of P.

Well, the sale price will just be P or 100% of P, minus 18%, the discounted price will be 100% - 18% = 82%, so the discounted price will be 82% of P.

`\begin{array}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{82\% of P}}{\left( \cfrac{82}{100} \right)P}\implies \boxed{0.82}\cdot P\qquad \impliedby \textit{discounted price}`