Question

In a sale, a shop

reduces all its prices by 15%. Calculate:

(ii) the original price of an article which was sold for $9.60

Answer 1

the original price was really "x", which oddly enough is the 100%.

Now, we know the prices are reduced by 15%, so 100% - 15% = 85%, so whatever "x" sold for, we know is 85% of "x", and we also know that's $9.60.

`\begin{array}{ccll} Amount&\%\\ \cline{1-2} x & 100\\ 9.60& 85 \end{array} \implies \cfrac{x}{9.60}~~=~~\cfrac{100}{85} \\\\\\ \cfrac{ x }{ 9.60 } ~~=~~ \cfrac{ 20 }{ 17 }\implies 17x=192\implies x=\cfrac{192}{17}\implies x\approx 11.29`