Multiple choice

The diluted milk contains only 8 liters of milk and rest is water. A new mixture whose concentration is 30% is to be formed by replacing mixture with pure milk. How many liters of the mixture shall be replaced with pure milk if there was initially 32 liters of water in the mixture?

  1. 3 liters

  2. 5 liters

  3. 8 liters

  4. 4 liters

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

Initial mixture has 8L milk and 32L water (40L total, 20% milk concentration). When we remove x liters of this mixture and add x liters of pure milk, milk increases by 0.8x (since we remove 20% milk but add 100% milk). To reach 30% concentration (12L milk in 40L), we need 8 + 0.8x = 12, giving x = 5 liters.

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