Answer:
The average rate of change for the depth of the river measured as feet per hour is approximately 0.3 feet/hour
Explanation:
The depth of the river in feet with time is given by the function with the attached
From the graph, we have;
The depth of the river at hour t = 9 is f(9) = 18 feet
The depth of the river at hour t = 18 is f(18) = 21 feet
The average rate of change, A(x), for the depth of the river measured as feet per hour is given as follows;

Therefore, for the river, we have;

The average rate of change for the depth of the river measured as feet per hour A(X) = 1/3 feet/hour
By rounding the answer to the nearest tenth, we have;
A(X) = 0.3 feet/hour.