Question

    Present ages of ‘A’, ‘B’ and ‘C’ are in the

    ratio 7:8:9, respectively. If present average age of ‘A’ and ‘C’ is 32 years, then find the age of ‘B’ when ‘C’ was 21 years old?
    A 10 years Correct Answer Incorrect Answer
    B 15 years Correct Answer Incorrect Answer
    C 17 years Correct Answer Incorrect Answer
    D 18 years Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let the present ages of ‘A’, ‘B’ and ‘C’ be ‘7x’ years, ‘8x’ years and ‘9x’ years, respectively. ATQ; (9x + 7x) ÷ 2 = 32 Or, 16x = 64 So, x = 4 So, present age of ‘C’ = 9 × 4 = 36 years Present age of ‘B’ = 8 × 4 = 32 years Difference between the ages of ‘B’ and ‘C’ = 36 – 32 = 4 years So, age of ‘B’ when ‘C’ was 21 years old = 21 – 4 = 17 years

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