We are given that
y-scale is a distance in miles
x-scale is a time in hours
and we are given
The graph of the distance a car travels at a constant speed passes through the points (0,0) and (2,136)
so, points would be
(0,0)
x1=0 , y2=0
(2,136)
x2=2 , y2=136
so, slope would be speed
because speed = distance / time
we can use slope formula
![m=(y_2-y_1)/(x_2-x_1)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/25uxp4sblay2143idvgkz738ukrk1vzo5g.png)
now, we can plug values
![m=(136-0)/(2-0)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/eu0lokco1cr612b07e8jf47ukrouj9utv5.png)
miles per hour
so, option-B..........Answer