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Question

Mathematics Question on permutations and combinations

How many words can be formed from the letters of the word DOGMATIC, if all the vowels remain together :

A

4140

B

4320

C

432

D

43

Answer

4320

Explanation

Solution

Total numbers of letters in the given word = 8 Total no. of 8 letters word formed = P (8, 8) = 8! No. of vowels = 3 (i.e., O, A, I) If we consider these three vowels as one letter, then the number of different words = 8 - 3 = 5 + 1 (as 3?? vowels are considered as 1 word) Hence, the total number of 8 letters in which vowel remains together = P (3 ×\times 3) ×\times P (6 ×\times 6) = 3! ×\times 6! = 6 ×\times 720 = 4320