How many different committees of 2 members can be formed from a group of 7 people?

Let $1,2,3,4,5,6,7,8$ be the women, and the men are denoted similarly, but with a hat, $\hat1$, $\hat2$, $\hat3$, $\hat4$, $\hat5$, $\hat6$.

The $1$ is not willing to work with $\hat 1$.

Now let us look at the counting strategy. Where do we count the configuration $2,3,4; \hat2,\hat3,\hat 4$?

  • Well, at point one at any rate, it is one valid case among the many $\binom 73\binom 53$, since $1$ and $\hat 1$ are both excluded.
  • Well, at point two also, it is one valid case among the many $\binom 83\binom 52$ cases, since $\hat 1$ is excluded.
  • Well, at point three again, it is one valid case among the many $\binom 72\binom 63$ cases, since $1$ is excluded.

For a correct answer, count all possible commitees, there are $\binom 83\binom 63=1120$ of them, and subtract those where the pair $1,\hat 1$ is in the commitee, there are $\binom 72\binom 52=210$ of them. So the answer is $$ \binom 83\binom 63 - \binom 72\binom 52 =1120 -210 =910\ . $$


How many different committees of 2 members can be formed from a group of 7 people?

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How many different committees of 2 men and 2 women can be formed from [#permalink]

How many different committees of 2 members can be formed from a group of 7 people?
  09 Oct 2020, 02:00

How many different committees of 2 members can be formed from a group of 7 people?

How many different committees of 2 members can be formed from a group of 7 people?

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How many different committees of 2 men and 2 women can be formed from a group of 12 people, half of whom are men?

A. 225

B. 450

C. 495

D. 900

E. 2,970

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Re: How many different committees of 2 men and 2 women can be formed from [#permalink]

How many different committees of 2 members can be formed from a group of 7 people?
  09 Oct 2020, 02:10

Bunuel wrote:

How many different committees of 2 men and 2 women can be formed from a group of 12 people, half of whom are men?

A. 225

B. 450

C. 495

D. 900

E. 2,970

6 men and 6 women to choose from
2 men and 2 women to be chosen

Total Selections = 6C2*6C2 = 15*15 = 225

Answer: Option A
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Re: How many different committees of 2 men and 2 women can be formed from [#permalink]

How many different committees of 2 members can be formed from a group of 7 people?
  09 Oct 2020, 02:13

6 Men 6 Women

Total no of ways
6C2 * 6C2
= (6*5/2) * (6*5/2)
= 15*15
=225
IMO A

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Re: How many different committees of 2 men and 2 women can be formed from [#permalink]

How many different committees of 2 members can be formed from a group of 7 people?
  09 Oct 2020, 02:13

Total number of people = 12

Men = 6 and Women = 6

No. of ways to form a committee with 2 Men and 2 Women = \(6C2 * 6C2\) = 15*15 = 225

Hence it's A

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Re: How many different committees of 2 men and 2 women can be formed from [#permalink]

How many different committees of 2 members can be formed from a group of 7 people?
  09 Oct 2020, 02:35

Total no of ways to choose committee of 2 men and 2 women = 6C2*6C2 = 15*15 = 225

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Re: How many different committees of 2 men and 2 women can be formed from [#permalink]

How many different committees of 2 members can be formed from a group of 7 people?
  09 Oct 2020, 02:39

Total: 12 => men : 6 and women: 6

Committtee: 2 men and 2 women: \(^6(C_2) * ^6(C_2)\)

=> 15 * 15 = 225

Answer A
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Re: How many different committees of 2 men and 2 women can be formed from [#permalink]

09 Oct 2020, 02:39

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How many committees of three people can be formed from 7 people?

So, there are 2300 different committees that can be formed.

How many committees of two members can be formed from a group of 7 people Mcq?

Answer: There are 7*6*5*4*3*2*1 ways to choose any group of 7, = 5040 ways. 604800/5040 = 120 different committees.

How many two person committees can be formed from a group of 6 people?

Such question has an answer 15 because first member is chosen from 6 people (so there are 6 possibilities), the second person is chosen from remaining five people so the number is 6⋅5=30 , but you have to divide the result by 2 because 2 people can be chosen in 2 ways but they still form the same team.

How many committees consisting of 5 can be formed from a group of 8 persons?

Bunuel wrote: A committee of 5 people is to be selected from 8 people. How many different committees are possible? 8C5 = 8C3 = 8 * 7 * 6 / 3! = 8 * 7 = 56.