CAT 2020 Slot 3 QA Question 20: Two alcohol solutions, A and B, are mixed in the proportion 1:3 by volume. The volume of the mixture is then doubled by adding solution A such that the resulting mixture has 72% alcohol. If solution A

Question

Two alcohol solutions, A and B, are mixed in the proportion 1:3 by volume. The volume of the mixture is then doubled by adding solution A such that the resulting mixture has 72% alcohol. If solution A

Accepted Answer

Let the first mixture contain 1 unit of A and 3 units of B. Its volume is 4 units.

The volume is doubled by adding 4 more units of A. Therefore, the final mixture has 5 units of A and 3 units of B.

Let the alcohol percentage in B be $b$%.

$\dfrac{5 	imes 60 + 3b}{8} = 72$

$\Rightarrow 300 + 3b

Two alcohol solutions, A and B, are mixed in the proportion 1:3 by volume. The volume of the mixture is then doubled by adding solution A such that the resulting mixture has 72% alcohol. If solution A has 60% alcohol, then the percentage of alcohol in solution B is