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

    Question

    There were 24 students in the class. One of them, who

    was 18 years old left the class and his place was filled up by a newcomer. If the average of the class was thereby lowered by 1 month, the age of the newcomer is
    A 14 years Correct Answer Incorrect Answer
    B 15 years Correct Answer Incorrect Answer
    C 16 years Correct Answer Incorrect Answer
    D 17 years Correct Answer Incorrect Answer

    Solution

    Let the average age of 24 men be x ⇒ Sum of age of 24 men = 24x If a man replaced, then average age of 24 men = (x – 1/12) ⇒ If a man replaced, then sum of age of 24 men = 24 (x – 1/12) = 24x – 2 Let weight of new man be y According to the question 24x – 18 + y = 24x – 2 ⇒ y = 24x – 2 – 24x + 18 ⇒ y = 16 ∴ Age of new comer is 16 years.

    Practice Next