Answer:
Explanation:
the average rate of change is the same as
the slope of a line m = (y2-y1)/(x2-x1)
to find if is positive of negative look at the line between the years given (for example between 1930 and 1940)
if from left to right the line goes downward the rate of change is negative
if from left to right the line goes upward the rate of change is positive