1. The problem asks for the total number of students who chose a school dinner. 2. From the frequency tree, we see two year groups: Year 7 and Year 8. 3. Year 7 students who chose school dinner: 15. 4. Year 8 students who chose school dinner: 32. 5. To find the total number of students who chose school dinner, add these two numbers: $$15 + 32 = 47$$ 6. Therefore, the total number of students who chose a school dinner is 47.