To determine which two points on a linear graph indicate a rate of change of 80 km per hour, we first need to understand that the rate of change (slope) can be calculated using the formula:
\[ \text{slope} = \frac{\text{change in distance}}{\text{change in time}} \]
In this case, we want the slope to equal 80 km/h.
Let's calculate the slope for each pair of points:
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(5, 400) and (6, 560): \[ \text{slope} = \frac{560 - 400}{6 - 5} = \frac{160}{1} = 160 \text{ km/h} \]
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(4, 480) and (6, 600): \[ \text{slope} = \frac{600 - 480}{6 - 4} = \frac{120}{2} = 60 \text{ km/h} \]
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(4, 320) and (6, 480): \[ \text{slope} = \frac{480 - 320}{6 - 4} = \frac{160}{2} = 80 \text{ km/h} \]
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(4, 400) and (6, 480): \[ \text{slope} = \frac{480 - 400}{6 - 4} = \frac{80}{2} = 40 \text{ km/h} \]
From the calculations above, the pair of points (4, 320) and (6, 480) gives a slope of 80 km/h.
So the correct response is: (4, 320) and (6, 480).