Question

1 litre of water is added to 5 litres of alcohol -water solution containing 40% alcohol strength. The strength of alcohol in the new solution will be:

• A. 30%
• B. 33%
• C. $33\frac{2}{3}$%
• D. $33\frac{1}{3}$%
• E. None of these

Answer 1

The correct option is D $33\frac{1}{3}$%

5 litres of alcohol-water solution containing 40% alcohol strength contains 2 litres alcohol.
When 1 litre water is added, the mixture becomes 6 litres in volume.
Hence, the strength of alcohol in the new solution will be $\frac{2}{6}\times 100=33\frac{1}{3}\%$