A classic counting problem is to determine the number of dif

A classic counting problem is to determine the number of different ways that the letters of

\"personnel\"\"personnel\"

can be arranged. Find that number.

Solution

There are

1 P
2 E
1 R
1 S
1 O
2 N
1 L

In PERSONNEL.

Thus, by permutation of like objects, there are

#ways = 9!/[1!2!1!1!1!2!1!] = 90720 WAYS [ANSWER]