Aptitude - Permutation and Combination - Discussion

Discussion Forum : Permutation and Combination - General Questions (Q.No. 14)
14.
In how many different ways can the letters of the word 'OPTICAL' be arranged so that the vowels always come together?
120
720
4320
2160
None of these
Answer: Option
Explanation:

The word 'OPTICAL' contains 7 different letters.

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

Then, we have to arrange the letters PTCL (OIA).

Now, 5 letters can be arranged in 5! = 120 ways.

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

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

Discussion:
36 comments Page 4 of 4.

Amogha said:   1 decade ago
Take the vowels as 1 unit and non-vowels, each as 1 unit.

Gayathri said:   1 decade ago
There are only 4! non vowels letter present can please tell me how you did with 5 !

Jiyas said:   1 decade ago
6 bells comments talling together &tall at the intervels of 2,4,6,8,10,&12 second respectively.

In 30 minits how many time do they tall together ?

Praveen said:   1 decade ago
There are 4 letters in this, so we can arrange those 4 letters in 4!ways and not in 5! ways..

Now, 4 letters can be arranged in 4!=24

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

Required number of ways =(24*6)=144

Chandu said:   1 decade ago
@Kishore

5!=5*4*3*2*1=120
3!=3*2*1=6

Kishore said:   1 decade ago
Can you please brief me about 5!letters = 120 ways and 3! = 6 ways


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