$\left. \begin{matrix} F=\left| q \right|vB\operatorname{Sin}\theta \Rightarrow \frac{{{F}_ {2}}}{{{F}_{1}}}=\frac{{{v}_{2}}}{{{v}_{1}}}  \\ {{F}_{2}}={{F}_{1}}+\frac{4}{100}{{F}_{1}}=1/04{{F}_{1}}  \\ \end{matrix} \right\}\Rightarrow \frac{{{v}_{2}}}{{{v}_{1}}} =1/04\Rightarrow \frac{{{v}_{1}}+1}{{{v}_{1}}}=1/04\Rightarrow {{v}_ {1}}+1=1/04{{v}_{1}}\Rightarrow 0/04{{v}_{1}}=1\Rightarrow {{v}_{1}} =25\frac{m}{s}$