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

    Question

    What is the ratio of the sum of the squares of the first

    8 natural numbers to the sum of the first 12 odd natural numbers?
    A 7:8 Correct Answer Incorrect Answer
    B 9:8 Correct Answer Incorrect Answer
    C 17:12 Correct Answer Incorrect Answer
    D None of the above Correct Answer Incorrect Answer

    Solution

    Sum of first 'n' odd numbers = n2

    Sum of square of first 'n' natural numbers. = {(n x (n + 1) x (2n + 1)}/6

    ATQ

    Sum of square of first 8 natural numbers = {8 X ([8 + 1) X (8 X 2 + 1) ] ÷ 6} = [(8 X 9 X 17) ÷ 6] = 204

    Sum of first 12 odd natural numbers = n2 = 122 = 144

    Required ratio = (204/144) = 17:12

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