1. The problem statement, all variables and given/known data From 5 consonants and 4 vowels, how many words can be formed consisting of 3 consonants and 2 vowels The book solved it using combination C(5,3) * C(4,2) * 5! = 7200 i.e I understand the 1st two term give the unique 5 words that can be formed with 5 consonants and 4 vowels and multiplying with 5! gives the permutation of all the 5 letters words 2. Relevant equations 3. The attempt at a solution I tried on my own and used permutation P(5,3) * P(4,2) = 720 I understand the book solution but then where am I wrong here?