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

    Question

    The average age of X, Y, and Z is 25 years, and the

    average age of X and Y was 19.5 years at the time of Z's birth. If X is now 30 years old, determine Z's age 8 years from now.
    A 22 years Correct Answer Incorrect Answer
    B 24 years Correct Answer Incorrect Answer
    C 26 years Correct Answer Incorrect Answer
    D 20 years Correct Answer Incorrect Answer

    Solution

    Let the current ages of X, Y, and Z be x, y, and z years, respectively. (x+y+z)/3=25 x + y + z = 25×3 x+y+z=75 30+y+z = 75 y+z = 45…...(i) (30-z) + (y-z) = 2×19.5 30+y-2z = 39 y-2z = 9…...(ii) subtract both the above equation we get, 3z = 36 z = 12 years age of Z after 8 years = 12+8 = 20 years

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