📢 Too many exams? Don’t know which one suits you best? Book Your Free Expert 👉 call Now!

    Question

    There are three classes P, Q and R. The average marks of

    class P is 75. The average marks of class Q is 80. The average marks of class R is 85. The average marks of class P and Q is 77, the average marks of class Q and R is83. Find the approximate average marks of three classes.
    A 62 Correct Answer Incorrect Answer
    B 80 Correct Answer Incorrect Answer
    C 50 Correct Answer Incorrect Answer
    D 69 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    By allegation method: So the ratio of students in class P to Q comes out to 3 : 2 & the ratio of students in class Q to Ris 2 : 3. Ratio of students in P, Q and R = 3 :2 : 3 So, average of all the classes = `(75xx3 + 80 xx2 + 85xx3)/(3+2+3)` = `(225+160+255)/8` = 80

    Practice Next
    More Average Questions

    Relevant for Exams:

    ask-question