To find out how many puzzles one student would complete, you can divide the total number of puzzles by the number of students.
So, you would calculate:
\[ \text{Puzzles per student} = \frac{80 \text{ puzzles}}{15 \text{ students}} \approx 5.3333 \]
Rounding this to the nearest tenth gives you 5.3.
Thus, the answer is 5.3.