How many words of 11letters could be Formed with all the vowels present only in the even places ,and the consonants only in the odd places,using letters of english alphabet each letter may appear only once.
Choices:  A) 21!  B) 26!/5!  C) 21! /(5! * 5! )  D) 21!* 5!/15!  E) 21!* 6!/5!
(21*20*19*18*17*16)*5! = 21! * 5! / 15!   ANSWER:21! /(5! * 5! )
<result>C</result>
How many words of 11letters could be Formed with all the vowels present only in the even places ,and the consonants only in the odd places,using letters of english alphabet each letter may appear only once.