Question

    Average of 16 observations calculated by a student was

    65 but when he again went through his observations he realised that he took value of three observations as 50, 59 and 40 in place of 90, 52 and 77 respectively and also realised that total observations taken by him was 15. Find the original average of all observations taken by him.
    A 77 Correct Answer Incorrect Answer
    B 72 Correct Answer Incorrect Answer
    C 70 Correct Answer Incorrect Answer
    D 74 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Sum of 16 observations = 16 × 65 = 1040 Original average = {1040 + (90 + 52 + 77) - (50 + 59 + 40)}/15 = 1110/15 = 74

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