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:
137 comments Page 11 of 14.
Naina said:
8 years ago
What are the number of ways to select 3 men and 2 women such that one man and one woman are always selected?
The Answer is 30 and solution is 4c2 * 5c1.
But, I don't think it is right according to the condition given in the question.
Someone help me.
The Answer is 30 and solution is 4c2 * 5c1.
But, I don't think it is right according to the condition given in the question.
Someone help me.
Riya said:
8 years ago
I did not understand how we got 21 for 7C5?
(1)
Abhijit said:
8 years ago
I tried to solve like this.
Out of 7 places first 3 places to be filled by men so.. 7*6*5 = 42*5 ways but order does not matter so removing redundancies (42*5)/3!.
Similarly Remaining two places can be filled in (10*9)/2!.
Final answer is same as 7C3 * 10C2.
Out of 7 places first 3 places to be filled by men so.. 7*6*5 = 42*5 ways but order does not matter so removing redundancies (42*5)/3!.
Similarly Remaining two places can be filled in (10*9)/2!.
Final answer is same as 7C3 * 10C2.
Tshewang chophel said:
8 years ago
How to get 7c3=35?
Sneha said:
8 years ago
Any one know the another method of solving?
(1)
Udoy said:
8 years ago
When do we add or multiply ?
Manuel said:
8 years ago
Help me knowing how to solve this kind of equation I'm doing my Student Individual Learning Plan.
I need to proof that I was correct so help me please.
I need to proof that I was correct so help me please.
Calesto said:
8 years ago
I don't understand why 7C5, in which 5is total number of persons to be chosen where 3 are men and remaining two are obviously women.
Thus, the answer should be 735.
Thus, the answer should be 735.
Teja said:
7 years ago
Here, ncr=nc(n-r).
Pratheeksha said:
7 years ago
Yes, 756 is a right ans.
Bcause out of 13(7men+6women) we have to select 5.Therefore
7men(5)6women,
7C3 X 6C2=35(15)=525,
7C4 X 6C1=35(6)=210,
7C5 X 6C0=21(1)=21,
=756.
Therefore, 756 is the answer.
Bcause out of 13(7men+6women) we have to select 5.Therefore
7men(5)6women,
7C3 X 6C2=35(15)=525,
7C4 X 6C1=35(6)=210,
7C5 X 6C0=21(1)=21,
=756.
Therefore, 756 is the answer.
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