Problem 11 (2004 AMC 8)

The numbers $-2, 4, 6, 9$ and $12$ are rearranged according to these rules: 1. The largest isn't first, but it is in one of the first three places. 2. The smallest isn't last, but it is in one of the last three places. 3. The median isn't first or last. What is the average of the first and last numbers?