 Hi and how are you all today? The question says in how many ways can the letter of the word assassination be arranged so that all the S are together? Let us discuss this question. Here the given word is for the letters of fascination. So in all there are 13 letters. Right? Now we need to find the number of permutation of words where SS come together. We take the 4s, 4s in one unit and this unit fills one place and the rest 9 letters will fill the remaining place. So now we have 10 letters that is SSSS plus 9 letters where a appear 3 times, 2 times and the rest have firstly verified how many letters we have then which letter is appearing how many times and how many letters are different. So before we apply theorem 4 we get the required number of permutation as 10 factorial divided by 3 factorial, 2 factorial, 2 factorial. Now here 10 factorial can be written as 10 multiplied by 9 multiplied by 8 and so on. 3 factorial can be written as 3 into 2 into 1, 2 factorial can be written as 2 into 1 and 2 factorial can be written as 2 into 1. On solving we have 10 into 9 into 8 into 7 into 6 into 5 that is equal to 151200 and this is our answer but here we used the theorem 4 of permutation and the knowledge of how to explain factorials which was the key ideas. Take care.