Let be x the unknown number. We know that 2/5 of that number is equal to 16, this means that 2/5 multiplied by x is equal to 16, hence the equation we are looking for is:
[tex]\frac{2}{5}x=16[/tex]
Solving for x we have:
[tex]\begin{gathered} \frac{2}{5}x=16 \\ x=\frac{16}{\frac{2}{5}} \\ x=\frac{16\cdot5}{2} \\ x=\frac{80}{2} \\ x=40 \end{gathered}[/tex]
Therefore the number we are looking for is 40
