Multiple choice general knowledge math & puzzles

729 ml of a mixture contains milk and water in ratio 7:2. How much of the water is to be added to get a new mixture containing half milk and half water?

  1. 400 ml

  2. 405 ml

  3. 300 ml

  4. 310 ml
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In 729 ml with milk:water = 7:2, milk = (7/9)*729 = 567 ml, water = 162 ml. Let x ml water be added to make ratio 1:1. Then 567/(162+x) = 1/1, so 567 = 162+x, giving x = 405 ml.

AI explanation

In 729 ml at a 7:2 milk-to-water ratio, milk = 729 × 7/9 = 567 ml and water = 729 × 2/9 = 162 ml. To make the mixture half milk and half water, water must equal milk, so water needs to reach 567 ml. That means 567 − 162 = 405 ml of water must be added, while the milk quantity stays fixed since only water is being added.

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