1. **Problem Statement:** Beatrice walks 1 km at 4 km/h and then 2 km at 4.5 km/h. Find her average speed for the whole journey. 2. **Step 1: Calculate the time taken for each part of the journey.** - Time = Distance ÷ Speed - For the first part: $$t_1 = \frac{1}{4} = 0.25 \text{ hours}$$ - For the second part: $$t_2 = \frac{2}{4.5} = \frac{2}{4.5} \approx 0.4444 \text{ hours}$$ 3. **Step 2: Calculate total distance and total time.** - Total distance $$D = 1 + 2 = 3 \text{ km}$$ - Total time $$T = t_1 + t_2 = 0.25 + 0.4444 = 0.6944 \text{ hours (approx)}$$ 4. **Step 3: Calculate average speed.** - Average speed $$v_{avg} = \frac{D}{T} = \frac{3}{0.6944} \approx 4.32 \text{ km/h}$$ 5. **Final answer:** Beatrice's average speed for the whole journey is approximately **4.32 km/h**.