2. Solved Papers
  3. CEE Kerala Engineering

CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2001

  • question_answer
    Everybody in a room shakes hands with everybody else. The total number of handshakes is 66. The number of persons in the room is:

    A)  11                         

    B)         12

    C)  13

    D)                                         14

    E)  15

    Correct Answer: B

    Solution :

    Let the number of persons in the room be n, then \[^{n}{{C}_{2}}=66\] \[\Rightarrow \]               \[\frac{n(n-1)}{2}=66\] \[\Rightarrow \]               \[{{n}^{2}}-n-132=0\] \[\Rightarrow \]               \[{{n}^{2}}-12n+11n-132=0\] \[\Rightarrow \]               \[(n-12)(n+11)=0\] \[\Rightarrow \]               \[n=12\]                               \[[\because n\ne -11]\]


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