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) | |||||||||||
|
||||||||||||
|
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| = (525 + 210 + 21) | ||||||||||||
| = 756. |
Discussion:
138 comments Page 1 of 14.
Jerry said:
7 days ago
How do you calculate that 6C2 and 7C3? Anyone explain me step by step.
Melvin N said:
10 months ago
nCr = nC(n-r) --> formula.
7C3 = 7C(7-3) = 7C4 = 35.
7C3 = 7C(7-3) = 7C4 = 35.
(7)
Kavya said:
1 year ago
How to solve this? Please explain.
(8)
Abhishek Singh said:
1 year ago
3 men & 2 woman = 7C3 * 5C2 = 525.
4 men & 1 woman = 7C4 * 5C1 = 210.
5 men = 7C5 = 21.
So, the answer is 756.
4 men & 1 woman = 7C4 * 5C1 = 210.
5 men = 7C5 = 21.
So, the answer is 756.
(10)
Adith said:
2 years ago
Thanks everyone for explaining the answer.
(9)
Khan said:
2 years ago
Why can't it be, 7C3 (at least 3 men) * 10C2 (any 2 may be men or women or both out of the remaining 10)?
(22)
Vishwanath said:
2 years ago
We need a minimum 3 men, so the maximum can be all 5 men in the committee.
3 men AND 2 women = 7C3 X 6C2 = 525.
4 men AND 1 women =7C4 X 6C1 = 210.
all 5 men = 7C5 = 21.
Add them 525 + 210 + 21 = 756.
3 men AND 2 women = 7C3 X 6C2 = 525.
4 men AND 1 women =7C4 X 6C1 = 210.
all 5 men = 7C5 = 21.
Add them 525 + 210 + 21 = 756.
(31)
Sumanth reddy said:
3 years ago
How it's changed from 7c4 to 7c3? Please explain me.
(23)
Suga said:
4 years ago
@All.
Here, some of the persons are confused in the second step because there was an incorrection where (7C4 x 6C1) + (7C5) were converted into + (7C3 x 6C1) + (7C2).
Here, some of the persons are confused in the second step because there was an incorrection where (7C4 x 6C1) + (7C5) were converted into + (7C3 x 6C1) + (7C2).
(15)
Abi said:
4 years ago
Anyone, Please explain this 7C3 * 6C1+7C2.
(11)
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