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 2 of 10.

Deepanesh said:   6 years ago
Why we are taking possibilities of vowels too?
(1)

Aradhy said:   6 years ago
@Deepanesh.

We are taking the possibilities of vowel because vowels can also change their position in the given arrangement.
(1)

Sundar said:   1 decade ago
@Madhusudan

5! = 5 Factorial = 1 x 2 x 3 x 4 x 5 = 120
(1)

Madhusudan said:   1 decade ago
Could you kindly let me know what is ( ! ).Howe 5! = 120 ?
(1)

Subbu said:   2 decades ago
7!=5040
(1)

Sri said:   2 decades ago
As vowels are together take (EAI) as single letter i.e. , total no of letters are 5 (L, N, D, G, {EAI}).

No of ways can arrange these 5 letters are 5! ways.

Now we arranged 5 letters (L, N, D, G, {EAI}).

Next we have to arrange E, A, I (they may be EAI/EIA/AEI/AIE/IAE/IEA).

All these combinations imply that vowels are together.

So we have to multiply 5! and 3!.
(1)

Jessie said:   1 decade ago
7 letter word = LEADING
CONDITION = VOWELS TO BE TOGETHER, HENCE (EAI) TO FOR A WORD
SO NO. OF WORDS = L,(EAI),D,N,G = 5
permuation to arrange 5 letters = nPr= n!/(n-r)!=5!/0!=5!
0! is assumed to be 1!)
EAI can be arranged among each other in = nPr = 3!/(3-3)= 3!
hence 5! x 3! = 120 x 6 = 720
(1)

Tanmay said:   8 years ago
In how many different ways can the letters of the word software be arranged in such a way that the vowels always come together?

Abhishek said:   8 years ago
I think it should be 3!*4!

Krishna said:   9 years ago
LEADING- vowels together in total 5 positions at L, E, A, D, and I.

Ex. For the first position - (EAI) - (remaining 4 lettersLNGD) - 4! * 3!

For total 5 positions - 5*3!*4! -720.


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