The Question was: In how many ways can the letters of the English alphabet be arranged so that there are exactly 10 letters between a and z?
My approach was the following: In between a and z, there are P(26,10) ways to arrange the 10 letters and then since 16 letters remain, we would also take into account the 16! arrangements of those letters. So, by the multiplication rule, the number of ways is 16!*P(26,10).