Question

    The average age of A and B is 18 years. If A is to be

    replaced by C, the average would be 17 years. The average age of C and A is 19 years. Find the age of A.
    A 20 yr Correct Answer Incorrect Answer
    B 23 yr Correct Answer Incorrect Answer
    C 16 yr Correct Answer Incorrect Answer
    D 25 yr Correct Answer Incorrect Answer

    Solution

    A + B = 2 × 18 = 36 yr B + C = 2 × 17 = 34 yr C + A = 2 × 19 = 38 yr On adding all three, 2 (A + B + C) = 36 + 34 + 38 = 108 ⇒ A + B + C = 54 ∴ A = (A + B + C) – (B + C) = 54 – 34 = 20 yr

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