[tex] \frac{a}{3} = \frac{b}{2} = \frac{c}{5} =420 \\
\frac{a+b+c}{3+2+5} = \frac{420}{10} \\
\frac{a}{3} = \frac{420}{10} =\ \textgreater \ a= \frac{420*3}{10} =\ \textgreater \ a= \frac{1.260}{10} =\ \textgreater \ a=126 \\
\frac{b}{2} = \frac{420}{10} =\ \textgreater \ b= \frac{420*2}{10} =\ \textgreater \ b= \frac{840}{10} =\ \textgreater \ b=84
\\ \frac{c}{5} = \frac{420}{10} =\ \textgreater \ c= \frac{420*5}{10} =\ \textgreater \ c= \frac{2.100}{10} =\ \textgreater \ c=210[/tex]
