Multiple choice

A vessel had acid and water. Adding 2L water made it 50% acid. Adding 15L acid more made it 80% acid. What was the original water:acid ratio?

  1. 5;3

  2. 3;5

  3. 7;8

  4. 4;5

  5. 2;3
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B Correct answer
AI explanation

Let the original acid be A and water be W; adding 2 liters of water makes the solution 50% acid, so A = W + 2. Adding 15 liters of acid to this new mixture makes it 80% acid, meaning A + 15 = 4 times the water, so A + 15 = 4(W + 2). Substituting A = W + 2 into the second equation gives W + 2 + 15 = 4W + 8, which simplifies to 3W = 9 and W = 3. Therefore, A = 5, and the original ratio of water to acid is 3:5.

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