Percents are represented by the following expression:
[tex]\text{Total}\cdot\text{percent (decimal form)=equivalent number to the percent}[/tex]Then, we can isolate the variable Total, to find b the cost of the manicure:
[tex]\begin{gathered} b\cdot0.20=4.60 \\ b=\frac{4.60}{0.20} \\ b=23 \end{gathered}[/tex]Manicure costs $23.