Question 1094501
<br>This is a simple application of the fundamental counting principle.<br>
There are 18 choices for the first officer chosen; it doesn't matter which office it is.
Then there are 17 choices left for the second officer chosen; then there are 16 choices left for the third officer chosen.<br>
So the number of ways the offices can be filled is
18*17*16<br>
Clearly, this is the permutation 18P3.  However, I see too many students who think every problem like this is purely either a combination or a permutation, so I encourage you to think of it simply as an application of the fundamental counting principle.