How many words can be formed from the letter of the word series with start with s and end with s

How many words can be formed from the letter of the word series with s

1.	How many words can be formed from the letter of the word series with start with s and end with s
Answer» Firstly fix s in starting and s in the end i.e. s,_,_,_,_,s. So no. Of ways are 4! Then s can also change its position by 2! ways. So no. of ways are 4!/2! .