To find the rate of change
Simply calculate the slope of the line
From the graph the two points are given
[tex](0,0),(5,150)[/tex]The slope of the line can be calculated using
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]Where m is the slope of the line
From the given points
[tex]\begin{gathered} x_1=0,x_2=5 \\ y_1=0,y_2=150 \end{gathered}[/tex]Substitute the values into the equation
This gives
[tex]m=\frac{150-0}{5-0}[/tex]Simplify further
[tex]\begin{gathered} m=\frac{150}{5} \\ m=30 \end{gathered}[/tex]Since the slope og the line is 30
This implies that the rate of change is $30