If a/2 = b/3 = c/4 then find ( (a + b + c)/b )-1.

Given, \(\frac{a}{2}\) = \(\frac{b}{3}\) = \(\frac{c}{4}\)

Here we can directly conclude that 

a = 2, b = 3, c = 4, hence

⇒ (\(\frac{a + b + c}{b}\))^-1 = (\(\frac{2 + 3 + 4}{3}\))^-1 = \(\frac{3}{9}\) = \(\frac{1}{3}\)