Multiple choice

A mixture of 12 liters of acid and water contains 30\% acid. How much water is to be drawn to make acid 40\%?

  1. 2

  2. 3

  3. 4

  4. 5
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The mixture contains 3.6 liters of acid (30% of 12L). To increase acid concentration to 40%, we remove only water, not acid. Set up: 3.6/(12-x) = 0.4, where x is water removed. Solving gives x = 3 liters. Removing 3L water leaves 9L total with 3.6L acid = 40%.

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