JEE Main & Advanced Mathematics Permutations and Combinations Question Bank Definition of permutation, Number of permutations with or without repetition, Conditional permutations

  • question_answer
    How many even numbers of 3 different digits can be formed from the digits 1, 2, 3, 4, 5, 6, 7, 8, 9 (repetition is not allowed)

    A) 224

    B) 280

    C) 324

    D) None of these

    Correct Answer: A

    Solution :

    The number will be even if last digit is 2, 4, 6 or 8 i.e., the last digit can be filled in 4 ways and remaining two digits can be filled in \[^{8}{{P}_{2}}\] ways. Hence required number of numbers are\[^{8}{{P}_{2}}\times 4=224\].

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