1. **State the problem:** We have a Venn diagram showing the number of people who went to Dinner, Movie, or both. We want to find how many people did exactly one activity. 2. **Identify the numbers:** - People who went only to Dinner: 25 - People who went to both Dinner and Movie: 13 - People who went only to Movie: 20 - The number 16 inside Dinner circle but outside overlap is unclear, but since 25 is already outside overlap, 16 might be a misread or extra info. We will consider only 25 (Dinner only), 13 (both), and 20 (Movie only) as per the problem statement. 3. **Formula:** Number of people who did exactly one activity = Number who did only Dinner + Number who did only Movie 4. **Calculate:** $$\text{Exactly one activity} = 25 + 20 = 45$$ 5. **Answer:** The number of people who did exactly one activity is **45**.