1. **State the problem:** We need to find the total distance travelled during a 50 second journey given the speed-time graph. 2. **Formula and concept:** Distance travelled is the area under the speed-time graph. Since speed is in m/s and time in seconds, the area under the graph gives distance in meters. 3. **Analyze the graph:** The graph consists of three parts: - From 0 to 10 seconds, speed increases linearly from 0 to 20 m/s (a triangle). - From 10 to 40 seconds, speed is constant at 20 m/s (a rectangle). - From 40 to 50 seconds, speed decreases linearly from 20 to 0 m/s (a triangle). 4. **Calculate areas:** - Triangle 1 (0 to 10 s): Area = \frac{1}{2} \times base \times height = \frac{1}{2} \times 10 \times 20 = 100 \text{ m} - Rectangle (10 to 40 s): Area = base \times height = 30 \times 20 = 600 \text{ m} - Triangle 2 (40 to 50 s): Area = \frac{1}{2} \times 10 \times 20 = 100 \text{ m} 5. **Total distance:** Sum of all areas = 100 + 600 + 100 = 800 meters. **Final answer:** The total distance travelled is **800 meters**.