SSC CHSL 6 Mar 2018 Shift 3 Paper

Milk in 1 litre mixture of vessel 1 = $\frac{3}{4}$ Milk in 1 litre mixture of vessel 2 = $\frac{7}{18}$ Milk in 1 litre of the new mixture = $\frac{1}{2}$ Let ratio of liquid from both vessels be $\mathit{x}:\mathit{y}$
⇒ $\left(\frac{3}{4}\mathit{x}\right)+\left(\frac{7}{18}\mathit{y}\right)=\frac{1}{2}\left(\mathit{x}+\mathit{y}\right)$
Multiply both sides by L.C.M. (4,18,2) = 36
⇒ $27\mathit{x}+14\mathit{y}=18\mathit{x}+18\mathit{y}$
⇒ $27\mathit{x}-18\mathit{x}=18\mathit{y}-14\mathit{y}$
⇒ $9\mathit{x}=4\mathit{y}$
⇒ $\frac{\mathit{x}}{\mathit{y}}=\frac{4}{9}=4:9$