1) A mixture contains alcohol and water in the ratio 4 : 3.If 5 litres of water is added to the mixture, the ratio becomes 4 : 5.The quality of alcohol in the given mixture is A) 10 litres B) 12 litres C) 11 litres D) 15 litres Answer: Option AExplanation:Let the quality of alcohol and water be 4x and 3xlitres respectively. Then, $\frac{4x}{3x+5}= \frac{4}{5} \Rightarrow20x=12x+20,x=25$ Quality of alcohol$=4x=4\times 2.5=10 litres$
