To find out how many puzzles one student would complete, 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 to the nearest tenth, one student would complete approximately:
\[ 5.3 \text{ puzzles} \]