# Two alcohol solutions, A and B, are mixed in the proportion - Quantitative Aptitude - Mixture

## CAT 2020 - Slot 3 - Quantitative Aptitude - Mixture - Question 18 - Two alcohol solutions, A and B, are mixed in the proportion

Q. 18: 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

##### 1. 94%2. 92%3. 90%4. 89%

18. B.

We are told that the A and B are mixed in the ratio 1:3

That means, one unit of A is mixed with 3 units of B

Observe that the total Volume is 1 + 3 = 4 units.

The volume is doubled by adding A, this implies that a quantity of 4 units of A is added to the existing 4units of the mixture.

The total volume will now be 4 + 4 = 8 units.

Of which three units are B and the rest 5 units are A. Hence the ratio of A to B in the final mixture is 5 : 3

We are told that A has a concentration of 60% alcohol and the final mixture has a concentration of 72% alcohol

300 + 3 × Concentration of B = 576

3 × Concentration of B = 576 – 300 = 276

3 × Concentration of B = 276 = 270 + 6

3 × Concentration of B = 270 + 6

Concentration of B = 270/3 + 6/3

Concentration of B = 90 + 2 = 92.

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