Two vessels contain milk : water as follows — Vessel A: 5 : 3 and Vessel B: 2 : 3. In what ratio should mixtures from A and B be combined to obtain a final mixture that is exactly half milk and half water?
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A2 : 5
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B3 : 5
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C4 : 5
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D7 : 3
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E4 : 5 (A : B)
Answer
Correct Answer: 4 : 5
Explanation
Introduction / Context:We have two mixtures with different milk fractions. To achieve a 1 : 1 milk-to-water target, use alligation on milk fractions to find the mixing ratio of the two sources.
Given Data / Assumptions:
- Vessel A milk fraction = 5/8 = 0.625.
- Vessel B milk fraction = 2/5 = 0.4.
- Target milk fraction = 1/2 = 0.5.
Concept / Approach:Alligation formula for fractions f1 (A) and f2 (B) to reach m: required A : B = (f2 − m) : (m − f1), ensuring f1 > m > f2 or vice versa with correct ordering.
Step-by-Step Solution:A : B = (0.4 − 0.5) : (0.5 − 0.625) in magnitudeUse absolute differences with proper sides: A : B = (m − f2) : (f1 − m) = (0.5 − 0.4) : (0.625 − 0.5)= 0.1 : 0.125 = 4 : 5
Verification / Alternative check:With 4 parts of A and 5 parts of B: milk fraction = (4*0.625 + 5*0.4) / 9 = (2.5 + 2) / 9 = 4.5 / 9 = 0.5.
Why Other Options Are Wrong:Other ratios give milk fraction different from 0.5. Only 4 : 5 balances the fractions.
Common Pitfalls:Reversing the alligation differences and obtaining 5 : 4 instead of 4 : 5.
Final Answer:4 : 5