Multiple choice

We have two solutions of milk. First contains 60% milk and the other contains 90% milk. If we mix the solutions in such a ratio that the new solution contains 85% milk, then in what ratio do we mix the solutions?

  1. 2 : 3

  2. 1 : 5

  3. 3 : 2

  4. 5 : 1

  5. 1 : 2
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B Correct answer
Explanation

Using alligation: (90-85) / (85-60) = 5 / 25 = 1 / 5.

AI explanation

Using the rule of alligation, we place the two initial concentrations of 60 and 90 on the left, and the target mean of 85 in the middle. The ratio of the first to the second solution is calculated as the difference between 90 and 85, written over the difference between 85 and 60. This gives a ratio of 5 to 25, which simplifies to 1 to 5.

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