Q.
The 120 permutations of MAHES are arranged in dictionary order, as if each were an ordinary five-letter word. The last letter of the 86th word in the list is
The first 24=4 ! words begin with A, the next 24 begin with E and the next 24 begin with H. So the 86th begins with M and it is the 86−72=14th such word. The first 6 words that begin with M begin with MA and the next 6 begin with ME. So the desired word begins with MH and it is the second such word. The first word that begins with MH is MHAES, the second is MHASE. Thus, E is the letter we seek.