Final answer:
The slope of the distance over time graph represents the car's speed, calculated by finding the rise over the run between two points. Using the points (2, 110) and (4, 220), the slope is 55, indicating the car travels at 55 miles per hour.
Step-by-step explanation:
The slope of a line on a graph represents the rate of change and can be calculated by finding the rise over the run between two points. For example, in a distance over time graph, the slope indicates the speed at which distance changes over time. To find the slope, you choose two points on the line and use the formula (y2 - y1)/(x2 - x1).
In the given problem, the student is asked to calculate the slope using the points (2, 110) and (4, 220). By applying the formula, we calculate the rise as 220 - 110 = 110 miles and the run as 4 - 2 = 2 hours, yielding a slope of 110 miles/2 hours = 55 miles per hour (mph). This means the car is traveling at a constant speed of 55 mph.
It's crucial to choose two points that are accurately represented on the graph, with a preference for points that are widely separated to minimize any potential error in reading the data. This ensures that any discrepancies have a minimal impact in the context of the overall interval.