Final answer:
Each folder costs $1.90.
Step-by-step explanation:
To find out how much each folder cost, we need to subtract the cost of the notebooks from the total bill and then divide by the number of folders. The cost of the notebooks is $12, and the total bill is $21.50. So the cost of the folders is $21.50 - $12 = $9.50. Since there are 5 folders, we divide $9.50 by 5 to find out the cost of each folder. $9.50 ÷ 5 = $1.90. Therefore, each folder costs $1.90.