How many different eight-letter permutations can be formed from the letters in the word parallel?

Using permutation in finding the eight-letter form from the letters in the word parallel, the answer would be 3360. This can be solved using this formula, n!/a! b! where n is the number of the letters in a word, a and b are the letters of the word that are repeated. There are 8 letters in parallel, 2 letter a's and 3 letter l's. So, 8!/2!3! = 3360.