11th Class Mental Ability Permutations and Combinations Question Bank Question - Permutation and Combination

  • question_answer
    A committee of 5 persons is to be formed out of 6 gents and 4 ladies. In how many ways this can be done, when at most two ladies are included?

    A) 186

    B) 168

    C) 136

    D) 169

    E) None of these

    Correct Answer: A

    Solution :

    Explanation Option (a) is correct. A committee of 5.persons, consisting of at most two ladies, can be formed n the following ways. (i) selecting 5 gents only out of 6. (ii) selecting 4 gents only out of 6 and one lady out of 4. (iii) selecting 3 gents only out of 6 and two ladies out of 4. In case I, the number of ways = \[^{6}{{C}_{5}}\] In case II, the number of ways =\[^{6}{{C}_{4}}{{\times }^{4}}{{C}_{2}}\] In case III, the number of ways = \[^{6}{{C}_{3}}{{\times }^{4}}{{C} _{2}}\] \[\therefore \] Required number of ways = \[^{6}{{C}_{5}}{{+}^{6}}{{C}_{4}}{{+}^{4}}{{C}_{1}}{{+}^{6}}{{C}_{3}}{{+}^{4}}{{C}_{2}}\] \[=\text{ }6+60+120=186\]


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