Multiple choice

There are three equal containers that are completely filled with different water-alcohol mixtures with water and alcohol in the ratio 2 : 3, 3 : 4 and 4 : 5 respectively. They are emptied into a bigger container. What fraction of alcohol in the bigger container should be replaced by water so that the resulting mixture has equal quantities of water and alcohol?

  1. 243:945

  2. 361:1890

  3. 143:1890

  4. 123:945

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

Calculate alcohol fraction in mixture: (5/9 + 4/7 + 5/9)/3 = 139/315. Set up replacement equation to achieve 1:1 ratio. The replacement fraction is 143:1890, making option C correct. Options A, B, and D have calculation errors.

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