Let's call x to the unknown number.
The 60% of x is computed as follows:
[tex]x\cdot60\text{ \% = x}\cdot\frac{60}{100}=0.6x[/tex]The 60% of x is equal to 12, then:
[tex]\begin{gathered} 0.6x=12 \\ \text{ Dividing by 0.6 at both sides:} \\ \frac{0.6x}{0.6}=\frac{12}{0.6} \\ x=20 \end{gathered}[/tex]
