2. Sample Papers
  3. JEE Main & Advanced

JEE Main & Advanced Sample Paper JEE Main Sample Paper-17

  • question_answer
    Number of ways in which 7 green bottles and 8 blue bottles can be arranged in a row if exactly 1 pair of green bottles is side by side, is (assume all bottles to be alike except for the colour)

    A)  84                                         

    B)  360

    C)  504                                       

    D)  None of these

    Correct Answer: C

    Solution :

     First, arrange 8 blue alike bottles, number of ways \[=1\] Now, select one gap out of nine gaps created  to put two green bottles; number of ways \[={{\,}^{9}}{{C}_{1}}\] Now, select five more gaps for other green bottles from remaining eight gaps; number of ways \[={{\,}^{8}}{{C}_{5}}\] Hence, total number of ways \[={{\,}^{9}}{{C}_{1}}{{.}^{8}}{{C}_{5}}=9.\frac{8.7.6}{1.2.3.}=72.=504\]


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