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combination and permutation question?
There are 20 people on the board of directors of a publicly listed company. Each pair of people are either friends or enemies with each other. Every person has exactly 6 enemies on the board. If every group of 3 directors form a committee, what is the total number of committees that are formed by all friends or all enemies?
1 Answer
- 9 years agoFavorite Answer
Hi Anoopam,
we should first see the possibilities of 1 person.................
so a person has 6 enemies and 14 friends.
he can form a committee of other 2 members by either selecting 2 from 6 E or 2 from 14F.
That can be done in 6C2 * 14C2.
Now, all the 20 persons have the possibility of 20 *6C2*14C2.
