Answer:
50 miles per hour
Explanation:
The speed can be found from a graph of distance versus time by looking at the slope of the graph. Here, the graph is a straight line, so the slope is constant. This means the speed is constant.
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It can be convenient to determine the speed by looking at distance for times that are 1 time unit apart. Here, that could be the distances at t=0 and at t=1. We see in that hour, the train traveled from 100 miles to 150 miles away from the station. Its speed was 150 -100 = 50 miles per hour.