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

    Question

    Six years ago, the ratio of ages of A to B was 7 : 5.

    After 4 years from now, the ratio of their ages will be 11 : 9. What is A’s age at present?
    A 24(1/2) years Correct Answer Incorrect Answer
    B 22(1/2) years Correct Answer Incorrect Answer
    C 23(1/2) years Correct Answer Incorrect Answer
    D 21(1/2) years Correct Answer Incorrect Answer

    Solution

    ATQ, Let the age of A and B six years ago be 7Q and 5Q respectively. Presents ages of A and B are (7Q + 6) and (5Q + 6) respectively. According to the question, (7Q + 6 + 4)/ (5Q + 6 + 4) = 11/9 ⇒ 10 × (7Q + 8) = 9 × (8Q + 8) ⇒ 63Q + 90 = 55Q + 110 ⇒ 63Q - 55Q = 110 - 90 ⇒ 8Q = 20 ⇒ Q = 20/8 ⇒ Q = 5/2 Hence the A's age is =  (7Q + 6)  [(5/2) × (7 + 6)] = 23(1/2) years

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