JEE Main & Advanced Mathematics Permutations and Combinations Question Bank Definition of combinations, Conditional combinations, Division into groups, Derangements

  • question_answer
    A man has 7 friends. In how many ways he can invite one or more of them for a tea party

    A) 128

    B) 256

    C) 127

    D) 130

    Correct Answer: C

    Solution :

    Required number of ways = \[{{2}^{7}}-1=127\]. {Since the case that no friend be invited i.e., \[^{7}{{C}_{0}}\] is excluded}.


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