We have:
Let x = unknown number
15% by x = 9 or
[tex]\frac{15}{100}\cdot x=9[/tex]And solve for x:
[tex]\begin{gathered} 100\cdot\frac{15}{100}\cdot x=9\cdot100 \\ 15x=900 \\ \frac{15x}{15}=\frac{900}{15} \\ x=60 \end{gathered}[/tex]Answer: the number is 60
