If there are 7 pairs of twins, and a committee will be formed with 3 members. In how many ways this committee formed in a way that no siblings in a group?  Choose the correct choice from the following answers:  A) 32  B) 24  C) 56  D) 144  E) 280
Firstly, there are 7 ways to choose 3 groups from the 4 groups. Hence 7C3.   Next, with the 3 groups chosen, there are 2^3 choices of choosing either one of the siblings.   Hence, the total number of ways are 7C3 * (2^3) = 280   280
<result>E</result>
If there are 7 pairs of twins, and a committee will be formed with 3 members. In how many ways this committee formed in a way that no siblings in a group?