Răspuns :
[tex]\frac{a}{2} = \frac{b}{3} =\frac{c}{5} \\a+b+c=30\\\frac{a}{2} = \frac{b}{3} => a=\frac{2b}{3} \\ \frac{b}{3} =\frac{c}{5} => c=\frac{5b}{3} \\\\[/tex]
si inlocuim in suma
[tex]\frac{2b}{3} +b+\frac{5b}{3} =30\\\\2b+3b+5b=90\\10b=90\\b=9[/tex]
a=6
c=15