Multiple choice

A 30 litre mixture contains wine and water in the respective ratio of 7 : 3. How much water (in litres) should be added to this mixture so that the ratio of wine to water is reversed?

  1. 49 L

  2. 39 L

  3. 37 L

  4. 40 L

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

Initial wine = 21L, water = 9L. To reverse the ratio to 3:7, let x be water added: 21 / (9 + x) = 3 / 7. Cross-multiply: 147 = 27 + 3x, so 3x = 120, x = 40.

AI explanation

The 30 litre mixture contains wine and water in a 7 to 3 ratio, resulting in 21 litres of wine and 9 litres of water. To reverse the ratio to 3 to 7, the 21 litres of wine must represent the new 3 parts, meaning each part is 7 litres. The required water is 7 parts times 7 litres, which equals 49 litres. Subtracting the 9 litres already present gives 40 litres of added water.

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