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:
99 comments Page 6 of 10.

Pooja said:   7 years ago
5! means? Explain

Tushar said:   8 years ago
@Shiva.

It means 5!.

Supriya said:   8 years ago
LEADING- V-3,(1 unit).
C-4 ,(4+ 1unit)=5!
n-7.
=5!*3!=120*6=720.

Sankardev said:   8 years ago
-L-D-N-G.

5!/(5-3)! = 120/2=60.
60*3!=60*6,
=360.

Jomson joy said:   10 years ago
In PACKET there are 2 vowels. Vowels came 2gether means 4! * 2! = 240.
Total words formed =6! (because of total letters) = 720.

Therefore 720 - 240 = 480.

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

How to decide based on the descriptive aptitude question ?

Juliana said:   8 years ago
How do you calculate combinations, can you do an example? Please.

Shafi said:   1 decade ago
@Mahantesh,

You are correct 3! and 4!, because you spitted vowels and consonants,

But to combine them vowels+consonants.

i.e. (4 consonants + 1 set of vowels) = 5!

And (3 vowels {1 set}) = 3!

So 5!*3! = 5x4x3x2x1x3x2x1=720.

Baidyanath jena said:   1 decade ago
When it comes to persons it should be combination.

Pema said:   1 decade ago
When it comes the question for arrangements, then it is a Permutation Or you all can remember it as keyword "PA" P=permutation and A=arrangement.

Likewise, for combination, it is all for selection purpose, remember keyword as "CS" c=combination,s=selection. Then apply formula for each. Easy.


Post your comments here:

Your comments will be displayed after verification.