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

    Question

    The father is 5 years older than the mother and five times

    as old as the son. If their current age sum is 110 years, after how many years will the father be twice as old as the son?
    A 25 yrs Correct Answer Incorrect Answer
    B 20 yrs Correct Answer Incorrect Answer
    C 17 yrs Correct Answer Incorrect Answer
    D 30 yrs Correct Answer Incorrect Answer

    Solution

    ATQ,

    Let the present age of the son and the father be 'x' years and '5x' years, respectively.

    Then, present age of the mother = (5x - 5) years

    So, x + 5x + (5x - 5) = 110

    Or, 11x - 5 = 110

    So, x = (110 + 5) ÷ 11 = 10

    Present ages of the son and father are 10 years and 50 years, respectively.

    For some 'y',

    (10 + y) × 2 = (50 + y)

    Or, 20 + 2y = 50 + y

    So, y = 30

    30 years hence from now, the father will be twice as old as the son

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