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.
Mayank said:
9 years ago
@Sudha.
As know this formula n!/r!(n-r)!.
7!/5!2!
3!/2!1!
The answer will be same .
What they have done is try to reduce one step.
As know this formula n!/r!(n-r)!.
7!/5!2!
3!/2!1!
The answer will be same .
What they have done is try to reduce one step.
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.
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?
Suvarna said:
1 decade ago
It takes more time to calculate 7c5 than 7c2& 3C2 than 3C1, to improve the speed we are doing like this.
Aswin said:
1 decade ago
Another question : how to select 6 people from a group of 10 so that two of them does not come together?
Jyoti said:
9 years ago
According to me, the final answer which displayed is wrong.
If we multiply 126 is coming.
If we multiply 126 is coming.
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.
Kunal said:
10 years ago
But why they did 7c5*3c2 as 7c2*3c1?
Why they directly not calculate 7c5*3c1?
Why they directly not calculate 7c5*3c1?
Dhayithri said:
9 years ago
Here we can also taken as 3c2 as 3c1 because factorial of those two is equal.
Zalak said:
1 decade ago
(7C5 x 3C2) = (7C2 x 3C1)
This step I can't understand. Please explain me.
This step I can't understand. Please explain me.
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