Aptitude - Permutation and Combination - Discussion
Discussion Forum : Permutation and Combination - General Questions (Q.No. 4)
4.
Out of 7 consonants and 4 vowels, how many words of 3 consonants and 2 vowels can be formed?
Answer: Option
Explanation:
Number of ways of selecting (3 consonants out of 7) and (2 vowels out of 4)
= (7C3 x 4C2) | |||||||||
|
|||||||||
= 210. |
Number of groups, each having 3 consonants and 2 vowels = 210.
Each group contains 5 letters.
Number of ways of arranging 5 letters among themselves |
= 5! |
= 5 x 4 x 3 x 2 x 1 | |
= 120. |
Required number of ways = (210 x 120) = 25200.
Video Explanation: https://youtu.be/dm-8T8Si5lg
Discussion:
65 comments Page 5 of 7.
Rishi said:
10 years ago
In question instead of how many words there should be how many arrangements.
Otherwise, a solution is wrong according to question.
Otherwise, a solution is wrong according to question.
Gezoi said:
8 years ago
7P3 * 5P2 =2520.
Then considering combining them accounting for repetitions we get = 5!/(3!*2!)=10.
Therefore =2520*10=25200.
Then considering combining them accounting for repetitions we get = 5!/(3!*2!)=10.
Therefore =2520*10=25200.
(1)
Machender said:
1 decade ago
Miss suchi, from given question it was clear that out of 7 consonants 3 consonants and 2 vowels of 4 vowels could considered.
Hehe said:
8 years ago
I don't think that it's supposed to be multiplied by 5! since it doesn't ask for the arrangement of the letters.
Atul Moundekar said:
9 years ago
This question is only based on a combination, they never told to find the arrangements. So the answer is 210.
Achu said:
1 decade ago
What's the need to take 5 here? They didn't mention any groupings here. Then what's the purpose to group?
Pranay said:
1 decade ago
The question doesn't mention "distinct" consonants or vowels. So repetition should be allowed.
Kaustav said:
1 decade ago
Combination 3 consonant and 2 vowels is still left. By adding forms 5! and then rest to find the total.
May said:
8 years ago
Why do 5!?
What if the consonants or vowels have repetition? Does it necessary to multiply with 5!?
What if the consonants or vowels have repetition? Does it necessary to multiply with 5!?
(5)
Anomiee said:
1 year ago
If the question is how many words we can form then why need to find the number of ways?
(6)
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