Aptitude - Permutation and Combination - Discussion
Discussion Forum : Permutation and Combination - General Questions (Q.No. 11)
11.
In how many ways can a group of 5 men and 2 women be made out of a total of 7 men and 3 women?
Answer: Option
Explanation:
| Required number of ways = (7C5 x 3C2) = (7C2 x 3C1) = |  |
7 x 6 | x 3 |  |
= 63. |
| 2 x 1 |
Discussion:
51 comments Page 2 of 6.
Divya said:
1 decade ago
How 3c2 change into 3c1?
Ankur anand said:
1 decade ago
Why combination why not permutation ?
Similar as that of the arranging of letters the people are diffrent so there can be many ways by permutation.
Similar as that of the arranging of letters the people are diffrent so there can be many ways by permutation.
Nirmal said:
1 decade ago
(7C2 x 3C1) = 7 x 6 x 3
How it happened explain please?
How it happened explain please?
Teja said:
1 decade ago
Hey see you said that 7c5*3c2 is long procedure. That the thing we take ncr formula. ?and second thing why we take that formula in this problem? am not?
Srikanth said:
1 decade ago
@teja. As this a problem f selection you use combination. It means calculating 7c5 is a bit more tedious when compared to calculating 7c2.
Moni said:
1 decade ago
For ex. Take 7C5, 5 is more than a half of 7. So we can use the formula nC (n-r) when are is more than half of n.
Similarly 3C2 is made as 3C1. I hope you have understood.
Similarly 3C2 is made as 3C1. I hope you have understood.
Niyati Bafna said:
1 decade ago
Are there any more problems, perhaps of a slightly advanced kind, on the net? If so, on which sites can they be found?
Vinod Rathod said:
1 decade ago
Lets do by this way :
As you said that (7c5*3c2) = (7c2*3c1).
7/5*3/2 = 7/2*3/1 = 63.
As you said that (7c5*3c2) = (7c2*3c1).
7/5*3/2 = 7/2*3/1 = 63.
Pooja said:
1 decade ago
I understood that thanks! we have to use nCr=nCn-r.
Chandan said:
1 decade ago
Why multiplication not addition?
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