Solved UPSC CDS/OTA Question
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Q · Mixture and AlligationMedium · 45s
In a mixture of 50 liters, the ratio of milk to water is 3:2. How much water must be added to make the ratio 3:4?
TopicMixture and Alligation
Question Typemultiple choice
DifficultyMedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained - no skipped algebra.
Initial mixture: 50 liters with milk : water = 3 : 2
→ Milk = (3/5) × 50 = 30 liters
→ Water = 20 liters
Let x liters of water be added.
New water = 20 + x
New total = 50 + x
New ratio:
30 / (20 + x) = 3 / 4
→ 4 × 30 = 3 × (20 + x)
→ 120 = 60 + 3x
→ 3x = 60
→ x = 20
Answer: Add 20 liters of water.
Final Answer: Option C - 20 liters