There are three containers of  equal capacity. The ratio of milk to water in the first container is 3:2, that in the second container is 7:3 and in the third container is 11:4, If all the liquids are mixed together, then the ratio of milk to water in the mixture will be

 Let  the quantity of  mixture of  each container be x, then

Milk in 1^st container = $\frac{3x}{5}$,   water $\frac{2x}{5}$

Milk in 2^nd container = $\frac{7x}{10}$, water = $\frac{3x}{10}$

 Milk in 3^rd container = $\frac{11x}{15}$,  water $\frac{4x}{15}$

 Milk in 3 containers = $$\begin{gathered} =\frac{3x}{5}+\frac{7x}{10}+\frac{11x}{15} \\ = \frac{18x+21x+22x}{30} \\ = \frac{61x}{30} \end{gathered}$$

Water = $\frac{2x}{5}+\frac{3x}{10}+\frac{4x}{15}$

Water = $\frac{29x}{30}$

          Ratio = $61 : 29$