Question

    A 1000-litre chemical solution consists of two substances,

    X and Y, in a 3:2 ratio. If 10% of the solution is removed and replaced with an equal amount of Y, what is the new ratio of X to Y in the final mixture?
    A 6:7 Correct Answer Incorrect Answer
    B 7:11 Correct Answer Incorrect Answer
    C 27:67 Correct Answer Incorrect Answer
    D 27:23 Correct Answer Incorrect Answer

    Solution

    ATQ;
    Quantity of X in the solution = (3/5) × 1000 = 600 litres
    Quantity of Y in the solution = (1000 – 600) = 400 litres
    Quantity of solution taken out = (0.1 × 1000) = 100 litres
    New ratio = {600 – (600 × 0.1)} : {400 – (400 × 0.1) + 100}
    = 540 : 460
    = 27:23

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