if we take 15.78 to be the 100%, what is the 15%?
[tex]\bf \begin{array}{ccll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
15.78&100\\
a&15
\end{array}\implies \cfrac{15.78}{a}=\cfrac{100}{15}\implies \cfrac{15.78\cdot 15}{100}=a[/tex]
