Question

A mixture contains acid and water in the ratio of 6 : 1. On adding 12 litres of water to the mixture, the ratio of acid to water becomes 3 : 2. The quantity of water (in litres) in the original mixture was: 
1. 3.5
2. 6
3. 4
4. 5

Answer 1

Correct Answer - Option 3 : 4

Given:

Acid and Water in ratio = 6 : 1

Water added to the mixture = 12 litres

The Final ratio of acid to water = 3 : 2

Calculation:

Let the amount of acid and water initially be 6x and x 

The initial ratio of acid to water = 6x : x

Adding water to mixture litres =  x + 12

According to question,

[6x/(x + 12)] = 3/2

⇒ 12x = 3x + 36

⇒ 9x = 36

⇒ x = 36/9 = 4

∴ The quantity of water in the original mixture is 4 litres