New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

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

    ratio 8:9:12, respectively. If present average age of ‘A’ and ‘C’ is 20 years, then find the age of ‘B’ when ‘C’ was 20 years old?
    A 12 years Correct Answer Incorrect Answer
    B 13 years Correct Answer Incorrect Answer
    C 14 years Correct Answer Incorrect Answer
    D 11 years Correct Answer Incorrect Answer

    Solution

    Let the present ages of ‘A’, ‘B’ and ‘C’ be ‘8x’ years, ‘9x’ years and ‘12x’ years, respectively. ATQ; (12x + 8x) ÷ 2 = 20 Or, 20x = 40 So, x = 2 So, present age of ‘C’ = 12 × 2 = 24 years Present age of ‘B’ = 9 × 2 = 18 years Difference between the ages of ‘B’ and ‘C’ = 24 – 18 = 6 years So, age of ‘B’ when ‘C’ was 20 years old = 20 – 6 = 14 years

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