EXPLANATION
Since Brian drives at a constant speed, in order to get the rate, we need to compute the slope, by applying the slope equation, as shown as follows:
[tex]\text{Slope}=\frac{y_2-y_1}{x_2-x_1}[/tex]Where (x_1,y_1)=(20,100) (x_2,y_2)= (50,140)
Plugging in the terms into the slope equation:
[tex]\text{Slope}=\frac{140-100}{50-20}=\frac{4}{3}[/tex]In conclusion, the distance will increase by 4 miles per hour.
