Aptitude - Permutation and Combination - Discussion

Discussion Forum : Permutation and Combination - General Questions (Q.No. 8)
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 3 of 7.

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?

Webuzzi said:   10 years ago
Why all should try this formula you will still get the right answer n!/(n!-r!)r!.

8!/(8!-5!)5! which will yield 56 then use same formula and solve for 10 combination 6 it will yield 210. Then multiply the former result by the later result. That is 56 multiplied by 210 will yield 11760.


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