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    Question

    From a barrel that contains pure alcohol, 10% alcohol is

    withdrawn and replaced with water. If the same process is repeated once more, then the quantity of alcohol remaining in the mixture would be 81 litres. Find the final quantity of water in the barrel.
    A 20 litres Correct Answer Incorrect Answer
    B 19 litres Correct Answer Incorrect Answer
    C 24 litres Correct Answer Incorrect Answer
    D 10 litres Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, Let the initial quantity of alcohol in the barrel be '100x' litres ATQ; 100x X (0.90)² = 81 Or, 81x = 81 Or, x = 1 So, original quantity of alcohol in the barrel = 100 X 1 = 100 litres Required quantity of water = 100 - 81 = 19 litres

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