Multiple choice

A container is full of mixture (40% water) of milk and water. A part of this mixture is replaced by another containing 81% milk and now the percentage of milk was found to be 74%. Find quantity of mixture replaced.

  1. 1/3

  2. 2/3

  3. 2/5

  4. 3/5

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

Initial mixture: 40% water means 60% milk. Let fraction replaced = f. After removing f portion and adding mixture with 81% milk, final milk % = (1-f) × 60% + f × 81% = 60% - 60%f + 81%f = 60% + 21%f = 74%. So 21%f = 14%, giving f = 14/21 = 2/3. Option B matches. This uses the replacement mixture formula.

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