[3]
[6C2x6C5 + 6C4x6C3]X2
A candidate is required to answer 7 out of 12 questions which are divided into two parts A and B , each containing 6 questions . he is not permited to answer more than 5 questions from either part , The number of ways , he can choose the 7 questions is
A (6) | B (6)
|
4 from here | 3 from here [similarly reverse]
|
5 from here | 2 from here [similarly reversed]
|
so u will get the above expression.