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

    Question

    The average of sixty numbers is 70 while the average of

    first thirty numbers and last thirty numbers is 75 and 85, respectively. Find the thirtieth term.
    A 600 Correct Answer Incorrect Answer
    B 520 Correct Answer Incorrect Answer
    C 640 Correct Answer Incorrect Answer
    D 785 Correct Answer Incorrect Answer

    Solution

    ATQ,

    Sum of sixty numbers = (60 × 70) = 4200

    Sum of the first thirty numbers = (30 × 75) = 2250

    Sum of the last thirty numbers = (30 × 85) = 2550

    So, thirtieth term = 2250 + 2550 - 4200 = 600

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