A jar full of whisky contains 40% alcohol. A part of this whisky is replaced by another containg 19% alcohol and now the percentage of alcohol was found to be 24%. What quantity of whisky is replaced ?
Choose one
A) 1/3
B) 2/3
C) 2/5
D) 3/5
E) 16/21
Let us assume the total original amount of whiskey = 10 ml ---&gt; 4 ml alcohol and 6 ml non-alcohol.   Let x ml be the amount removed ---&gt; total alcohol left = 4-0.4x   New quantity of whiskey added = x ml out of which 0.19 is the alcohol.   Thus, the final quantity of alcohol = 4-0.4x+0.19x ----&gt; (4-0.21x)/ 10 = 0.24 ---&gt; x = 160/21 ml.   Per the question, you need to find the x ml removed as a ratio of the initial volume ---&gt; (160/21)/10 = 16/21.   Hence, 16/21 is the correct answer.
<result>E</result>
A jar full of whisky contains 40% alcohol. A part of this whisky is replaced by another containg 19% alcohol and now the percentage of alcohol was found to be 24%. What quantity of whisky is replaced ?