1. **State the problem:** We need to find the total distance traveled by the train given its speed over time as a piecewise linear function.
2. **Understand the problem:** Distance traveled is the area under the speed-time graph. Since speed is in miles/hr and time in hours, the area under the curve gives distance in miles.
3. **Analyze the graph:** The speed increases linearly from 0 to 60 miles/hr in the first hour, stays constant at 60 miles/hr from 1 to 9 hours, then decreases linearly from 60 miles/hr to 0 in the last hour (9 to 10 hours).
4. **Break the graph into sections:**
- Section 1 (0 to 1 hr): Speed increases linearly from 0 to 60.
- Section 2 (1 to 9 hr): Speed is constant at 60.
- Section 3 (9 to 10 hr): Speed decreases linearly from 60 to 0.
5. **Calculate area for each section:**
- Section 1 is a triangle with base 1 hr and height 60 miles/hr:
$$\text{Area}_1 = \frac{1}{2} \times 1 \times 60 = 30$$ miles
- Section 2 is a rectangle with width 8 hr and height 60 miles/hr:
$$\text{Area}_2 = 8 \times 60 = 480$$ miles
- Section 3 is a triangle with base 1 hr and height 60 miles/hr:
$$\text{Area}_3 = \frac{1}{2} \times 1 \times 60 = 30$$ miles
6. **Sum all areas to find total distance:**
$$\text{Total distance} = 30 + 480 + 30 = 540$$ miles
7. **Final answer:** The train travels **540 miles**.
Train Distance 512B38
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