Question

Notebooks costs 1.20 each. This weekend they will be on sale for $0.80. What percentage is the sale

Answer 1

so, if we take 1.20 to be the 100%, what is 0.80 off of it anyway?


`\bf \begin{array}{ccll} amount&\%\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 1.20&100\\ 0.80&p \end{array}\implies \cfrac{1.20}{0.80}=\cfrac{100}{p}\implies p=\cfrac{0.80\cdot 100}{1.20}`