Question

Miley’s music has a sale on music CDs. All music CDs are discounted 15%. Mariana’s receipt indicates that she saved $3 on her CD purchase. What is the full price of her music CD before the discount?

Answer 1

she saved $3, and we know the discount is 15%, so her savings is that 15%, thus we know 15% of that purchase is 3.

let's say the full price is x, and therefore the 100%, if we know 3 is the 15%, what is x?

$\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 3&15\\ x&100 \end{array}\implies \cfrac{3}{x}=\cfrac{15}{100}\implies \cfrac{3\cdot 100}{15}=x\implies 20=x$