In how many ways can the letters of the word ASSASSINATION be arranged so that all the S’s are together?
In the given word ASSASSINATION, there are 4 ‘S’. Since all the 4 ‘S’ have to be arranged together so let as take them as one unit.
The remaining letters are= 3 ‘A’, 2 ‘I’, 2 ‘N’, T
The number of letters to be arranged are 9 (including 4 ‘S’)
Using the formula where n is number of terms and p1, p2 p3 are the number of times the repeating letters repeat themselves.
Here p1= 3, p2= 2, p3 = 2
Putting the values in formula we get