KVPY Sample Paper KVPY Stream-SX Model Paper-26

  • question_answer
    Three randomly chosen non-negative integers x, y and z are found to satisfy the equation \[x+y+z=10\]. Then, the probability that z is even

    A) \[\frac{1}{2}\]

    B) \[\frac{36}{55}\]

    C) \[\frac{6}{11}\]

    D) \[\frac{5}{11}\]

    Correct Answer: C

    Solution :

    We have, x + y + z = 10
    Total number of sample space \[{{=}^{12}}{{C}_{2}}=66\]
    Number of possibilities of z is even
    \[z=0{{\Rightarrow }^{11}}{{C}_{1}}\]\[\Rightarrow \,\,\,\,\,\,z=2{{\Rightarrow }^{9}}{{C}_{1}}\]\[\Rightarrow \,\,\,\,\,\,z=4{{\Rightarrow }^{9}}{{C}_{1}}\]\[\Rightarrow \,\,\,\,\,\,z=6{{\Rightarrow }^{5}}{{C}_{1}}\]\[\Rightarrow \,\,\,\,\,\,z=8{{\Rightarrow }^{3}}{{C}_{1}}\]
    \[\Rightarrow \,\,\,\,\,\,z=10{{\Rightarrow }^{1}}{{C}_{1}}\]
                Total =11+ 9+7+5+3+1=36, Required probability \[=\frac{36}{66}=\frac{6}{11}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner