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Aptitude - Permutation and Combination - Discussion

Discussion Forum : Permutation and Combination - General Questions (Q.No. 8)
Permutation and Combination
8.
In how many ways a committee, consisting of 5 men and 6 women can be formed from 8 men and 10 women?
266
5040
11760
86400
None of these
Answer: Option
Explanation:
Required number of ways = (8C5 x 10C6)
= (8C3 x 10C4)
= 8 x 7 x 6 x 10 x 9 x 8 x 7
3 x 2 x 1 4 x 3 x 2 x 1
= 11760.
Discussion:
61 comments Page 6 of 7.
Vimala said:   1 decade ago
No need to multiply with 11! because they did not ask for the arrangement of the person. We need to concentrate only on the selection of person for the committee.
Younisali.syed said:   1 decade ago
I agree with this answer but when you see question no: 4 in that he selected and then arranged in this problem he only selected.

Any one tell me why so?
Flair said:   1 decade ago
In this question don't give importance to arrangements. Like ABC=ACB=BAC they are same. Take this example with person.
Siva said:   1 decade ago
Different arrangement of digits in a number gives different numbers, but arrangement doesn't alter the composition of a committee. So no need to calculate no.of arrangements. All arrangements give the same committee.
Nishat Parwez said:   1 decade ago
The correct formula for the mentioned question is n!/r!( n-r)!..

This makes the concept clear. Totally agree with @Diwakar.
Vishesh bakshi said:   1 decade ago
Am always confused whether to multiply or add in between this two cases. How to determine it correctly can any one help me out on this?
Poonam said:   1 decade ago
Do not use the formula which does not exist for actual solution. That formula is for permutation which you given. Please explain in another way.
Bala said:   1 decade ago
Ya its confusing please tell in simple way.
Priya said:   10 years ago
When I'm solving it directly like 8C5 and 10C6 means I'm getting wrong answer.
Karthika said:   10 years ago
Why we are applying the ncr=n-r formula in the second step?

What is the purpose of using where we should we use this?
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