Two vessels A and B contain solution of acid and water. In A and B the ratio of acid and water are 7 : 3 and 4 : 1, respectively. They are mixed in the ratio 1 : 2. What is the ratio of acid and water in the resulting solution?

In 1 unit of vessel A, quantity of acid = $$\frac{7}{10}\times1=\frac{7}{10}$$

Quantity of water = $$\frac{3}{10}\times1=\frac{3}{10}$$

Similarly, in 2 units of vessel B, quantity of acid = $$\frac{4}{5}\times2=\frac{8}{5}$$

Quantity of water = $$\frac{1}{5}\times2=\frac{2}{5}$$

=> Ratio of acid and water in the resulting solution = $$[(\frac{7}{10}+\frac{8}{5}):(\frac{3}{10}+\frac{2}{5})]$$

= $$\frac{23}{10}:\frac{7}{10}$$

= $$23:7$$

=> Ans - (C)