let's say is "x", so "x" is then the 100%, and we know that 161 is the 35%, alrite then,
[tex]\bf \begin{array}{ccll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
x&100\\
161&35
\end{array}\implies \cfrac{x}{161}=\cfrac{100}{35}\implies x=\cfrac{161\cdot 100}{35}[/tex]