How many words with or without meaning can be formed using 3 vowels and 2 consonants?

Answer

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Hint: Count the number of vowels and consonants in the word DAUGHTER. Let the counts be x, y respectively. The required words should have 2 vowels and 3 consonants in it. So the no. of words that contains 2 vowels and 3 consonants which can be formed from the letters of DAUGHTER is ${}^x{C_2} \times {}^y{C_3}$

Complete step-by-step answer:
We are given to find the number of words that can be formed from the letters of the word DAUGHTER which contains 2 vowels and 3 consonants.
The given word is DAUGHTER. This word has 3 vowels, A, U, E, and 5 consonants, D, G, H, T and R.
So the required words should have 2 vowels from A, U and E; 3 consonants from D, G, H, T and R.
And the order of the letters is not specific, which means the letters can be used in any order. So we have to use combinations.
So the no. of words will be ${}^3{C_2} \times {}^5{C_3}$, selecting any 2 from 3 vowels and selecting any 3 from 5 consonants.
$
  {}^n{C_r} = \dfrac{{n!}}{{r!\left( {n - r} \right)!}} \\
  {}^3{C_2};n = 3,c = 2 \\
  {}^3{C_2} = \dfrac{{3!}}{{2!\left( {3 - 2} \right)!}} = \dfrac{{3 \times 2 \times 1}}{{2 \times 1 \times 1!}} = \dfrac{6}{2} = 3 \\
  {}^5{C_3};n = 5,c = 2 \\
  {}^5{C_3} = \dfrac{{5!}}{{3!\left( {5 - 3} \right)!}} = \dfrac{{5 \times 4 \times 3 \times 2 \times 1}}{{3 \times 2 \times 1 \times 2!}} = \dfrac{{120}}{{12}} = 10 \\
  \therefore No.of words = {}^3{C_2} \times {}^5{C_3} = 3 \times 10 = 30 \\
$
Therefore, 30 words can be formed from the letters of the word DAUGHTER each containing 2 vowels and 3 consonants.

Note: A Permutation is arranging the objects in order. Combinations are the way of selecting the objects from a group of objects or collection. When the order of the objects does not matter then it should be considered as Combination and when the order matters then it should be considered as Permutation. Do not confuse using a combination, when required, instead of a permutation and vice-versa.

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The word is 'INVOLUTE'
               Number of consonants = 4
                     Number of vowels = 4.
The words formed should contain 3 vowels and 2 consonants.
The problems becomes:
(i)                 Select 3 vowels out of 4.

                   Number of selections =
(ii)         Select two consonants out of 4.
                    Number of selections = 
(iii)  Arrange the five letters (3 vowels + 2 consonants) to form words.
                        Number of permutations = 5!
(iv)  Apply fundamental principle of counting:

                 Number of words formed = 

                                                  = 

                                                  = 4 x 6 x 120 = 2880  
Hence, the number of words formed  = 2880

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