Question

15 litres of mixtures contains 20% alcohol and the rest water. If 3 litres of water be mixed with it, the percentage of alcohol in the new mixture would be

• A. $15$
• B. $16\frac{2}{3}\%$
• C. $17\%$
• D. $18\frac{1}{2}\%$

Answer 1

The correct option is B $16\frac{2}{3}\%$

Alcohol in $15$ litre mixture $=20\%$ of $15$

$\Rightarrow \frac{20}{100}\times 15=3$ litre

When $3$ litre water is added then mixture $=18$ litre

Then percentage of alcohol in new mixture $=\frac{3}{18}\times 100=\frac{100}{6}=16\frac{2}{3}\%$