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    Select the number from among the given options that can replace the question mark (?) in the following series.139 136 131 124 115 ? 91
    Question

    Select the number from among the given options that can replace the question mark (?) in the following series.
    139 136 131 124 115 ? 91

    A.

    106

    B.

    109

    C.

    104

    D.

    101

    Correct option is C

    Given:
    139, 136, 131, 124, 115, ?, 91
    Logic: The differences are increasing by 2: 3, 5, 7, 9, 11, 13,...
    139 - 3 = 136
    ​136 - 5 = 131
    ​131 - 7 = 124
    ​124 - 9 = 115
    Similarly,
    ​115 - 11 = 104
    104 - 13 = 91
    Thus, the correct option is (c).

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