Option C and Option E are the correct answers.
Lets understand the question before we start solving for it.
The question tells us that a committee needs to be formed of n people for which will be chosen from n
example: a committed of two people to be chosen from two couples married couples. Then it further adds that n is a two digit even integer.
Now the questions asks us to "
Select for No married couples the number of different committees that can be formed if no two people who are married to each other are allowed to serve on the committee, and select for Only married couples the number of different committees that can be formed if the committee must consist only of married couples". Now lets try solving the question.So for the first part question in which it asks us "
Select for No married couples the number of different committees that can be formed if no two people who are married to each other are allowed to serve on the committee.The answer to this will be
2^(n) i.e Option C because for each positive we will be having 2 options like for the first position at the committee we could either select the husband or the wife for that position, same for the second and so on. It's a bit confusing to lets try to understand it with an example.
Example: A committee of 2 people needs to be selected from 2 married couples, such that no two people are married. Now lets take couple-1 to be (x and y) and couple-2 to be (a and b). Lets see with the by just casually counting and without using any formula or property to check how many such pairs can be formed. So the pairs will be: (x and a) or (x and b) or (y and a) or (y and b) so the committee can any of these four scenarios. Similarly as discussed above if we solve this by using the formula then it can be solved like: 2*2 => 2^2 => 4.
So as we can see from this example whenever we are asked of this type of scenario instead of manually calculating the pairs we could just do 2^(number of positions in committee) to find the answer.
Now lets solve for the second question which asks us "S
elect for Only married couples the number of different committees that can be formed if the committee must consist only of married couples".To get the answer for this question we just have to assume one simple thing then this question will be easily solved like any other Permutation & Combination question. So while solving this we just need to assume each couple as a single unit only which would mean that if their are 20 people i.e. 10 couples then while solving the question we need to consider them as 10 people only instead of 20, we are assume this because of the condition mentioned in the question which says that "Committee must consist of both Husband and Wife or Both Husband and Wife will be in the committee".
So the answer to this question will be
Option E i.e. n!/(n!/2)^(2). So from here we can say that
Option C i.e. 2^(n) & Option E i.e. n!/(n!/2)^(2) are our answers.Bunuel
A certain company is forming a committee of n people to be chosen from n married couples, where n is a two-digit even number.
Select for
No married couples the number of different committees that can be formed if no two people who are married to each other are allowed to serve on the committee, and select for
Only married couples the number of different committees that can be formed if the committee must consist only of married couples. Make only two selections, one in each column.