A bottle contains spirit and water in the ratio 1:4 and another identical bottle contains spirit and water in the ratio 4:1. In what ratio should the mixtures in the two bottles be mixed to get a new mixture in which the ratio of spirit to water is 1:3?

  1. A. 5:1
  2. B. 6:1
  3. C. 10:1
  4. D. 11:1

Correct Answer: D. 11:1

Explanation

Concentration of spirit in the first bottle is 1/5 and in the second is 4/5. The desired concentration is 1/4. Using alligation, the ratio of the first to the second mixture is (4/5 - 1/4) : (1/4 - 1/5) = (11/20) : (1/20) = 11:1.

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