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