Multiple choice

In a mixture composed of acid and water, where for every 5 litres of acid in the mixture, there is 1 litre of water. If 3 litres of water is added to the mixture, the new mixture contains twice as much acid as water. Find the quantity of acid in the original mixture.

  1. 8 litres

  2. 10 litres

  3. 12 litres

  4. 15 litres

  5. 20 litres
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Original ratio of acid to water is 5:1. Let acid = 5x, water = x. After adding 3L water, the ratio is 5x / (x + 3) = 2 / 1. Solving 5x = 2x + 6, we get 3x = 6, so x = 2. Original acid = 5 * 2 = 10 litres.

AI explanation

Let the initial quantities of acid and water in the mixture be 5x and x. When 3 litres of water is added, the new quantity of water becomes x + 3. The new mixture contains twice as much acid as water, giving the equation 5x = 2(x + 3). Solving this yields 5x = 2x + 6, so 3x = 6 and x = 2. The original quantity of acid is 5x, which is 10 litres.

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