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:
97 comments Page 9 of 10.

Bhavik said:   1 decade ago
How to read these nPr ?

Santosh kumar pradhan said:   1 decade ago
Total member 7
out of which 5 consonant and 3 vowels
take 3 vowls as a 1
hen number of consonant will arrange 5! ways
and these 3 vowels will arrange 3! ways
though,5!*3!=720

Shiva said:   1 decade ago
Why we have taken 5 (4 + 1) ?

Siva said:   1 decade ago
Permutations and combinations always make me to confuse much.

How to decide based on the descriptive aptitude question ?

Pavan@9966606261 said:   1 decade ago
@mayur.

You just look when ever you open the new exercise there will be availability of basic formulas. If you go through them half of the task would be finished easily. Have a good day buddy.

Bharti said:   1 decade ago
Thanks a lot. I had confusion before your explanations. Thanks a lot.

Mayur said:   1 decade ago
How it came like nPr formula and how you have solve it? please let me know.

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)

Moaned said:   1 decade ago
I am not getting

Laxmikanth said:   1 decade ago
When should we take the one or more letters as a single unit and why?


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