In how many different ways can the letters of the word 'OPTICAL' be arranged so that the vowels always come together?	Choose the correct choice from the following answers
A) 610  B) 720  C) 825  D) 920  E) None of these
Explanation :   The word 'OPTICAL' has 7 letters. It has the vowels 'O','I','A' in it and these 3 vowels   should always come together. Hence these three vowels can be grouped and considered as a   single letter. That is, PTCL(OIA).   Hence we can assume total letters as 5. and all these letters are different.   Number of ways to arrange these letters = 5! = [5 x 4 x 3 x 2 x 1] = 120   All The 3 vowels (OIA) are different   Number of ways to arrange these vowels among themselves = 3! = [3 x 2 x 1] = 6   Hence, required number of ways = 120 x 6 = 720. Answer : Option 720
<result>B</result>
In how many different ways can the letters of the word 'OPTICAL' be arranged so that the vowels always come together?