Answer: 5.
Step-by-step explanation:
You can see the attached figure for better understanding.
A pentagonal prism has 2 bases (the bottom and top faces), each pentagonal, and 5 lateral faces.
The pentagon is a figure with 5 sides. Hence, from each side, the prism will have one lateral face that goes from one base to the other.
The figure attached shows a pentagonal prism where you can see what I explained.