How many different ways can letters be arranged so that vowels always come together?

Answer [Detailed Solution Below]

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Given:

The word is DRASTIC.

Calculation:

The vowels in the word = A, I.

The number of vowel is 2.

The number of consonants = 5 [D R S T C]

To find the total number of ways we have to assume two vowel as one letter like [A I] D R S T C

The number of ways to arrange these 6 letters = 6! 

And total number of ways to arrange vowels = 2!

So the total number of ways = 6! × 2! = 1440

∴The number of ways that the vowels always come together is 1440. 

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2] In what ways the letters of the word "PUZZLE" can be arranged to form the different new words so that the vowels always come together?

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Answer: D

Answer with the explanation:

The word PUZZLE has 6 different letters.

As per the question, the vowels should always come together.
Now, let the vowels UE as a single entity.
Therefore, the number of letters is 5 [PZZL = 4 + UE = 1]
Since the total number of letters = 4+1 = 5
So the arrangement would be in 5P5 =

=
= 5! = 5*4*3*2*1 = 120 ways.

Note: we know that 0! = 1

Now, the vowels UE can be arranged in 2 different ways, i.e., 2P2 = 2! = 2*1 = 2 ways

Hence, the new words, which can be formed after rearranging the letters = 120 *2 = 240

As we known z is occurring twice in the word ‘PUZZLE’ so we will divide the 240 by 2.

So, the no. of permutation will be = 240/2 = 120

3] In what ways can a group of 6 boys and 2 girls be made out of the total of 7 boys and 3 girls?

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Answer: C

Answer with the explanation:

We know that nCr = nC[n-r]

The combination of 6 boys out of 7 and 2 girls out of 3 can be represented as 7C6 + 3C2
Therefore, the required number of ways = 7C6 * 3C2 = 7C[7-6] * 3C[3-2] =

= 21

Hence, in 21 ways the group of 6 boys and 2 girls can be made.

4] Out of a group of 7 boys and 6 girls, five boys are selected to form a team so that at least 3 boys are there on the team. In how many ways can it be done?

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Answer: C

Answer with the explanation:

We may have 5 men only, 4 men and 1 woman, and 3 men and 2 women in the committee.

So, the combination will be

as we know that

nCr=

So, [7C3 * 6C2] + [7C4 * 6C1] + [7C5]
Or,

+
+

Or, 525 +210+21 = 756

So, there are 756 ways to form a committee.

5] A box contains 2 red balls, 3 black balls, and 4 white balls. Find the number of ways by which 3 balls can be drawn from the box in which at least 1 black ball should be present.

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Answer: A

Answer with the explanation:

The possible combination could be [1 black ball and 2 non-black balls], [2 black balls and 1 non- black ball], and [only 3 black balls].

In the below solved problem, every thing is okay, but if we have $4$ consonants then why we are giving $5!$? and is this a combination problem? how to distinguish?

Question: In how many different ways can the letters of the word 'OPTICAL' be arranged so that the vowels always come together?

Answer: 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 $= [120*6] = 720$.

Exercise :: Permutation and Combination - General Questions

11. 

In how many ways can a group of 5 men and 2 women be made out of a total of 7 men and 3 women?

Answer: Option A

Explanation:

Required number of ways = [7C5 x 3C2] = [7C2 x 3C1] =

7 x 6x 3
= 63.2 x 1

How many ways vowels come together?

[i] Let us suppose 3 vowels as one unit and the number of permutations in E,I,U is3!. Now, we can arrange 4 consonants +1units of vowels in P,I,C,R,EIU =5 ways. So, permutations will be 5!. Hence, the number of permutations on which 3 vowels occur together =5!

How many ways can the letters be arranged so that all the vowels come together word is corporation?

So, the total number of ways of arranging the letters of the word 'CORPORATION' be arranged so that the vowels always come together are 7!

How many ways word arrange can be arranged in which vowels are not together?

Hence, the answer is 36.

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