Multiple choice

In a scientific laboratory, a researcher has a 25-litre solution containing 80% water. To meet specific experimental requirements, the researcher needs to adjust the solution to precisely 60% water concentration. How much water in millilitres (ml) should the researcher remove from the solution to achieve this desired concentration?

  1. 12.5

  2. 1,250

  3. 12,500

  4. 1,25,000
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Initial solution: 25L total, 80% water = 20L water, 5L solute. We remove x liters of water. New water = 20-x, new total = 25-x. We want (20-x)/(25-x) = 0.6. 20-x = 15 - 0.6x, so 5 = 0.4x, x = 12.5L. 12.5L = 12,500 ml.

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