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    Question

    There are 15 numbers such that average of first 12

    numbers is 65 while the average of last five numbers is 76. Find the 12th number, if the ratio between 11th and 12th number is 13:7, respectively.
    A 140 Correct Answer Incorrect Answer
    B 100 Correct Answer Incorrect Answer
    C 130 Correct Answer Incorrect Answer
    D 180 Correct Answer Incorrect Answer
    E 150 Correct Answer Incorrect Answer

    Solution

    Sum of first 12 numbers = (12 × 65) = 780 Sum of last 5 numbers = (76 × 5) = 380 Sum of 11th and 12th number = (780 - 380) = 400 So, 12th number = 400 × (7/20) = 140

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