This table shows the linear relationship of the water level in a tank and time.

Time (hr) Water level (ft)
0 50
2 40
4 30
6 20
Enter the rate of change of the water level, in feet per hour.

1 answer

The rate of change of the water level can be calculated by finding the slope of the line connecting two points on the graph.

Using the formula for slope:
Rate of change = (change in y-coordinate) / (change in x-coordinate)

Between points (0, 50) and (2, 40), there is a decrease of 10 feet in the water level over a span of 2 hours.

Rate of change = (40 - 50) / (2 - 0)
= -10 / 2
= -5 feet per hour

Therefore, the rate of change of the water level is -5 feet per hour.