Final answer:
Each pack of permanent markers costs $15.
Step-by-step explanation:
To find the cost of each pack of permanent markers, we need to subtract the cost of the poster paper from the total cost. The cost of the poster paper is given as $11. So, the cost of the permanent markers is $101 - $11 = $90.
Since there are 6 identical packs of permanent markers, we can divide the total cost of $90 by 6 to find the cost of each pack. $90 ÷ 6 = $15.
Therefore, each pack of permanent markers costs $15.