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