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4th Class Mental Ability Days and Dates & Possible Combinations Question Bank Days and Dates & Possible Combinations

  • question_answer
    How many possible combinations of one pencil and one eraser from 3 pencils and 3 erasers can be formed?

    A)  10                               

    B)  9                                

    C)  12                               

    D)  15

    Correct Answer: B

    Solution :

      Pencils \[({{P}_{1}},{{P}_{2}},{{P}_{3}})\] and Erasers  \[({{E}_{1}},{{E}_{2}},{{E}_{3}})\]                         Possible combinations \[({{P}_{1}},{{E}_{1}}),({{P}_{1}},{{E}_{2}}),({{P}_{1}}{{E}_{3}}),({{P}_{2}},{{E}_{1}}),({{P}_{2}},{{E}_{2}}),({{P}_{2}}{{E}_{3}}),({{P}_{3}},{{E}_{1}}),({{P}_{3}},{{E}_{2}}),({{P}_{3}},{{E}_{3}})\] or Three elements are in Pencil set and three elements are in eraser set. So, Possible combinations \[=3\times 3=9.\]


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