Question

The rate of change is $ _ million per year.

Answer 1

The slope of the graph is the difference of y- values over the difference in x-values.

`Slope=(\Delta y)/(\Delta x)`

The diffrence in y- values is

`\Delta y=450-50=400`

and the difference in x-values is

`1999-1991=8`

Hence, the rate of change (or the slope ) of the graph is

`\text{slope = }(400)/(8)`
`\text{slope}=(\$50)/(yr)`

which is our answer!