[tex] \frac{a}{3} = \frac{b}{5} \\ \frac{a}{6} = \frac{c}{7} [/tex]
Din prima => b = [tex] \frac{5a}{3} [/tex]
Din a doua => c = [tex] \frac{7a}{6} [/tex]
[tex]a + \frac{5a}{3} + \frac{7a}{6} =46 | *6 \\
6a + 10a + 7a = 276 \\
23a = 36 => a = \frac{276}{23} = 12 \\
b = \frac{ 5*12 }{3} = 20 \\ c = \frac{ 7*12 }{6} = 14[/tex]