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    Question

    What will come in place of the question mark (?) in the following series? 

    18, 21, 45, 138, 555,

    ?
    A 2778 Correct Answer Incorrect Answer
    B 1255 Correct Answer Incorrect Answer
    C 2250 Correct Answer Incorrect Answer
    D 2650 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, The given series follows the following pattern: 18 X 1 + 3 = 21 21 X 2 + 3 = 45 45 X 3 + 3 = 138 138 X 4 + 3 = 555 555 X 5 + 3 = 2778

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