RAJASTHAN ­ PET Rajasthan PET Solved Paper-2010

  • question_answer
    The total number of ways of selecting five letters from the letters of the word 'INDEPENDENT' is

    A)  72              

    B)  27

    C)  36              

    D)  64

    Correct Answer: A

    Solution :

     Word'INDEPENDENT here,\[1-1,N-3,D\] \[2,E-3,P-1,T-1\] Selection can be made by the following number of ways (i) If all the letters are distinct, then no. of ways\[{{=}^{6}}{{C}_{5}}=6\] (ii) If three are different and two letters are same, then no. of way\[{{=}^{3}}{{C}_{1}}{{.}^{5}}{{C}_{3}}=30\] (iii) If two letters are different and three are same, then ways\[{{=}^{2}}{{C}_{1}}{{.}^{5}}{{C}_{2}}=20\] (iv) If two letters are same another two letters are same and one letter is different, then no. of ways \[{{=}^{3}}{{C}_{2}}{{.}^{4}}{{C}_{1}}=12\] (v) If three letters are same and another two letters are same, then ways\[{{=}^{2}}{{C}_{1}}{{.}^{2}}{{C}_{1}}=4\] \[\therefore \]Total number of ways \[=6+30+20+12+4=72\]


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