To determine which two points on a linear graph indicate a rate of change of 80 km per hour, we can use the formula for the slope (rate of change) between two points \((x_1, y_1)\) and \((x_2, y_2)\):
\[ \text{slope} = \frac{y_2 - y_1}{x_2 - x_1} \]
For a rate of change of 80 km/h, we want:
\[ \frac{y_2 - y_1}{x_2 - x_1} = 80 \]
Now we can evaluate each pair of points:
-
(4, 320) and (6, 480):
- \(y_2 - y_1 = 480 - 320 = 160\)
- \(x_2 - x_1 = 6 - 4 = 2\)
- Slope = \( \frac{160}{2} = 80 \)
-
(4, 400) and (6, 480):
- \(y_2 - y_1 = 480 - 400 = 80\)
- \(x_2 - x_1 = 6 - 4 = 2\)
- Slope = \( \frac{80}{2} = 40 \)
-
(5, 400) and (6, 560):
- \(y_2 - y_1 = 560 - 400 = 160\)
- \(x_2 - x_1 = 6 - 5 = 1\)
- Slope = \( \frac{160}{1} = 160 \)
-
(4, 480) and (6, 600):
- \(y_2 - y_1 = 600 - 480 = 120\)
- \(x_2 - x_1 = 6 - 4 = 2\)
- Slope = \( \frac{120}{2} = 60 \)
From our calculations, the pair of points that gives a rate of change of 80 km/h is (4, 320) and (6, 480).