Question

    The average of twenty-five numbers is 65 while the average

    of first fifteen numbers and last fifteen numbers is 70 and 80, respectively. Find the fifteenth term.
    A 600 Correct Answer Incorrect Answer
    B 520 Correct Answer Incorrect Answer
    C 625 Correct Answer Incorrect Answer
    D 785 Correct Answer Incorrect Answer

    Solution

    ATQ,

    Sum of twenty-five numbers = (25 × 65) = 1625

    Sum of the first fifteen numbers = (15 × 70) = 1050

    Sum of the last fifteen numbers = (15 × 80) = 1200

    So, fifteenth term = 1050 + 1200 - 1625 = 625

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