To do this, you can first write the sentence in mathematical language, that is
[tex]\frac{2}{5}x=\frac{3}{20}[/tex]Now, you can solve for x
[tex]\begin{gathered} \frac{2}{5}x=\frac{3}{20} \\ \text{ Multiply by 5 on both sides of the equation} \\ 5\cdot\frac{2}{5}x=\frac{3}{20}\cdot5 \\ 2x=\frac{3\cdot5}{20} \\ 2x=\frac{15}{20} \\ \text{ Multiply by }\frac{1}{2}\text{ into both sides of the equation} \\ 2x\cdot\frac{1}{2}=\frac{15}{20}\cdot\frac{1}{2} \\ \frac{2x}{2}=\frac{15}{20\cdot2} \\ x=\frac{15}{40} \\ \text{Simplify} \\ x=\frac{5\cdot3}{5\cdot8} \\ x=\frac{3}{8} \end{gathered}[/tex]Therefore, the number is 3/8.
