Question

    A factory has a 720-litre solution of acid and water mixed

    in a 5:4 ratio. If 30% of this solution is removed and replaced with an equal amount of water, what is the new ratio of acid to water in the final mixture?
    A 25:21 Correct Answer Incorrect Answer
    B 7:11 Correct Answer Incorrect Answer
    C 4:5 Correct Answer Incorrect Answer
    D 5:11 Correct Answer Incorrect Answer

    Solution

    ATQ;
    Quantity of acid in the solution = (5/9) × 720 = 400 litres
    Quantity of water in the solution = (720 – 400) = 320 litres
    Quantity of solution taken out = (0.3 × 720) = 216 litres
    New ratio = {400 – (400 × 0.3)} : {320 – (320 × 0.3) + 216}
    = 280 : 440
    = 7:11

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