If the number of words of 4 letters formed with n different letters of an alphabet such that at
Channel: Doubtnut
Date: 12/04/2020

If the number of words of 4 letters formed with n different letters of an alphabet such that at least on letter is repeated in the word is 936, then n= (A) 4 (B) 5 (C) 6 (D) none of these