Aptitude - Permutation and Combination - Discussion

Discussion Forum : Permutation and Combination - General Questions (Q.No. 10)
10.
In how many different ways can the letters of the word 'DETAIL' be arranged in such a way that the vowels occupy only the odd positions?
32
48
36
60
120
Answer: Option
Explanation:

There are 6 letters in the given word, out of which there are 3 vowels and 3 consonants.

Let us mark these positions as under:

(1) (2) (3) (4) (5) (6)

Now, 3 vowels can be placed at any of the three places, marked 1, 3, 5.

Number of ways of arranging the vowels = 3P3 = 3! = 6.

Also, the 3 consonants can be arranged at the remaining 3 positions.

Number of ways of these arrangements = 3P3 = 3! = 6.

Total number of ways = (6 x 6) = 36.

Discussion:
59 comments Page 5 of 6.

Jilsa said:   8 years ago
What if we want to arrange letters of *Machine* such that vowels occupy odd places?

Usha said:   7 years ago
Then what is the use of vowels arranged in odd position?

I think it's wrong.

PRAKASH S said:   1 decade ago
I really don't understand why we are doing that.

How we are taken 3p3 = 6?

Subhadeep said:   1 decade ago
We can consider the seventh position also. So I feel the answer is wrong.

Aditya said:   9 years ago
How can we solve the same question taking 'FATHER' as the given word?

Dev said:   10 years ago
It can be done by 6x5x4x3x2 divide by 2 and again divide by 10 = 36.

Omshiva said:   6 years ago
@Keshav.

By Using the Gauss method. The correct answer is A.
(6)

Navi said:   7 years ago
Simple:

(DTL) * (EAI).

(3*2*1) * (3*2*1).
(6)*(6) = 36.
(2)

Bonface said:   9 years ago
Why we also considering the positions of the consonants?

Gayathri said:   1 decade ago
Why we use permutation concept instead of combination.


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