Aptitude - Permutation and Combination - Discussion
Discussion Forum : Permutation and Combination - General Questions (Q.No. 1)
1.
From a group of 7 men and 6 women, five persons are to be selected to form a committee so that at least 3 men are there on the committee. In how many ways can it be done?
Answer: Option
Explanation:
We may have (3 men and 2 women) or (4 men and 1 woman) or (5 men only).
 Required number of ways |
= (7C3 x 6C2) + (7C4 x 6C1) + (7C5) | |||||||||||
|
||||||||||||
|
||||||||||||
| = (525 + 210 + 21) | ||||||||||||
| = 756. |
Discussion:
138 comments Page 9 of 14.
Gokul said:
1 decade ago
It is simple to identify the given problem is permutation or combination. It is just by common sense ya. In permutation, there is arrangement of things. But in combination it is selection. I hope you understand.
Ankit said:
1 decade ago
Friends, please tell me how to identify whether question is of permutation or combination?
Pandu said:
1 decade ago
@Priyanka das.
7C2 has taken since in the last case we need to take 5 men so that you may be understood, its actually 7c5 when in nCr if n value is more than half of n value we need to use formula as nC(n-r)so implies n=7, r=5 since r is more than half of n we used as 7C(7-5) it becomes 7C2. OK I HOPE you got it.
7C2 has taken since in the last case we need to take 5 men so that you may be understood, its actually 7c5 when in nCr if n value is more than half of n value we need to use formula as nC(n-r)so implies n=7, r=5 since r is more than half of n we used as 7C(7-5) it becomes 7C2. OK I HOPE you got it.
D.Yogapriya said:
1 decade ago
Is there any other simple way to solve this 1st problem?
Ashok said:
1 decade ago
Please give a correct explanation to combination and permutation?
VATSAL KHANDELWAL said:
1 decade ago
Dear @Akash,
You mustn't try these if you don't even know the meaning of "c".
Else what I can say is that.
"c" simply means "combination".
But you can't understand if you haven't read the chapter.
You mustn't try these if you don't even know the meaning of "c".
Else what I can say is that.
"c" simply means "combination".
But you can't understand if you haven't read the chapter.
Akash said:
1 decade ago
Can anyone please explain what does C imply here?
Deus Simon said:
1 decade ago
The questions influencable but you did not talk about the of an event to occur.
Priyanka Das said:
1 decade ago
7C2 means 2 men are selected from 7 men.
Krishan said:
1 decade ago
Anyone could explain why we used 7c2 in second step?
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