JEE Main & Advanced JEE Main Paper (Held On 12-Jan-2019 Morning)

  • question_answer
    Let S = {1, 2, 3, ..., 100}. The number of non- empty subsets A of S such that the product of elements in A is even is [JEE Main Online Paper Held On 12-Jan-2019 Morning]

    A) \[{{2}^{50}}({{2}^{50}}-1)\]                        

    B) \[{{2}^{50}}-1\]

    C) \[{{2}^{50}}+1\]                    

    D)   \[{{2}^{100}}-1\]

    Correct Answer: A

    Solution :

    Here, S = {1, 2, 3, ..... 100} So, the number of non-empty subsets A of S such that the product of elements in A is even = Total non empty subsets-subsets with product of element is odd \[={{2}^{100}}-1-[{{2}^{50}}-1]={{2}^{100}}-{{2}^{50}}={{2}^{50}}({{2}^{50}}-1)\]


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