A solution of 45% alcohol is mixed with a solution of 60% alcohol in the ratio of 2 3. In what ratio should the resultant solution be mixed with a 72% alcohol solution to get a 66% alcohol solution?

1 : 2

The concentration of Alcohol in after the 1st mixture = \(\frac{45*2 + 60*3}{2/3}\) = 54%.

⇒ Let it be mixed with 72% alcohol solution in m : n ratio.

According to the question,

⇒ \(\frac{54 x m + 72 x n}{m + n}\) = 66,

⇒ 54m + 72n = 66m + 66n

⇒ 12m = 6n

⇒ m : n = 1 : 2.

Hence in Ratio 1 : 2, the resultant solution should be mixed with a 72% alcohol solution to get a 66% alcohol solution.