To find out how many puzzles one student would complete, we can divide the total number of puzzles completed by the number of students.
Given that 22 students completed 80 puzzles:
\[ \text{Puzzles per student} = \frac{\text{Total puzzles}}{\text{Total students}} = \frac{80}{22} \approx 3.63636 \]
Now, rounding to the nearest tenth gives us:
\[ 3.6 \]
So, one student would complete approximately 3.6 puzzles.