Multiple choice

A jar full of whisky contains 40% alcohol. A part of this whisky is replaced by another containing 19% alcohol and now the percentage of alcohol was found to be 26%. What is the quantity of whisky replaced ?

  1. 1/3

  2. 2/3

  3. 2/5

  4. 3/5

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Using the allegation method: (19-26) and (40-26) gives ratio 14:7, which is 2:1. The part replaced is 2/(2+1) = 2/3.

AI explanation

Using the rule of alligation on the alcohol percentages, the ratio of the first whisky to the second whisky is (26 - 19) to (40 - 26), which is 7 to 14 or 1 to 2. This means the initial mixture is 1 part and the added mixture is 2 parts of the total 3 parts. The quantity of whisky replaced is 2 out of 3 parts, or 2/3.

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