Aptitude - Permutation and Combination - Discussion

Discussion Forum : Permutation and Combination - General Questions (Q.No. 2)
2.
In how many different ways can the letters of the word 'LEADING' be arranged in such a way that the vowels always come together?
360
480
720
5040
None of these
Answer: Option
Explanation:

The word 'LEADING' has 7 different letters.

When the vowels EAI are always together, they can be supposed to form one letter.

Then, we have to arrange the letters LNDG (EAI).

Now, 5 (4 + 1 = 5) letters can be arranged in 5! = 120 ways.

The vowels (EAI) can be arranged among themselves in 3! = 6 ways.

Required number of ways = (120 x 6) = 720.

Video Explanation: https://youtu.be/WCEF3iW3H2c

Discussion:
98 comments Page 3 of 10.

Ali said:   9 years ago
@Avishek

No. of vowels is 3Es and the can only be together in this pattern {EEE}. There is only 1 way of choosing so 1! = 1 * 1 = 1.

We are to consider 3Es as a single alphabet because they are together. So we have L, M, N, T,{EEE} ie 5 letters now in all.

Now of way of choosing 5 letters = 5! (5 * 4 * 3 * 2 * 1) = 120.
Finally, we multiply 120 * 1 = 120 ie. the number of ways of arranging the letters so that the vowels are always together.

Avishek kadel said:   9 years ago
In how many ways the letters of word ELEMENT can be arranged so that vowels are always together?

Can anyone solve this?

Akshay said:   9 years ago
@Navan.

15c11 = 15!&div(15-11)! * 11!

Navan said:   9 years ago
I have one question.

How many ways 11players selected from 15 players?

Please give me the answer.

Brian said:   10 years ago
Correct me if I'm wrong but,

There are 7 letters:

L E A D I N G

3 vowels and 5 non-vowels.

I got the part where we need to permutate 3 and 5, resulting with 3!*5!. But aren't there also several other positions that these vowels could be positioned?

For Example:

AIELDNG is one factor, another factor is LAIEDNG, another factor is LDAIENG.

As you can see, the positions of the 3 vowels with each other are the same, and the order of non-vowels in the word is also the same, but I only changed the position of the starting point for the vowel permutations, starting from the first position, to the second, to the third. So, I believe that the answer should be 3!*5!*5. Since there are 5 different ways you could represent the same order of vowels in different positions with the same order of non-vowels.

Please do correct me if I'm wrong or if I misunderstood the question

Sowmya said:   9 years ago
@Xyz.

C,M,B,N,T,N,(O,I,A,I,O)=> C,M,B,T,N,(O,I,A)=> 6! ways.

Vowels alone can be rearranged themselves in 3! ways.
So 6! * 3! = 2160.
Hope this is right.

Xyz said:   9 years ago
How many letters can be formed from COMBINATION if vowels are kept together?

Please give the solution.

Otieno said:   9 years ago
Where has 5! come from? Please explain me.

Rakesh said:   9 years ago
In leading 5! * 3! ways we can fill all vowels come together.

Prajwal said:   9 years ago
Does it have an another method to find the solution?


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