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    Question

    Sum of squares of three consecutive numbers is 770. Find

    the sum of first and third number.
    A 32 Correct Answer Incorrect Answer
    B 30 Correct Answer Incorrect Answer
    C 44 Correct Answer Incorrect Answer
    D 46 Correct Answer Incorrect Answer

    Solution

    Let the numbers be (x – 1), x and (x + 1) => (x – 1)2 + x2 + (x + 1)2 = 770 => x2 – 2x + 1 + x2 + x2 + 2x + 1 = 770 => 3x2 = 770 - 2 => x2 = 768/3 => x2 = 256 => x = 16 Required sum = (16 – 1) + (16 + 1) = 32

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