Question

The number of words which can be made out of the letters of the word ‘MOBILE’ when consonants always occupy odd places, is

A) 20

(B) 36

(C) 30

(D) 720

Answer 1

Correct option (B) 36

The word ‘MOBILE’ has three even places and three odd places. It has 3 consonants and 3 vowels. In three odd places we have to fix up 3 consonants, which can be done in 3P3 ways. Now in the remaining three places we have to fix up the remaining three vowels, which can be done in 3P3 ways.

Therefore, the total number of ways = 3P3x 3P3 = 36.