the speed is 
miles per hour > is false
step-by-step explanation:
we know that
a relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form 
or 
in a proportional relationship the constant of proportionality k is equal to the slope m of the line and the line passes through the origin
the graph shown in the figure represent a direct variation
the slope of the line represent the speed
for the point )
substitute the values of x and y
the linear equation is equal to
statements
case a) it takes 
hours to go 
miles
the statement is true
because
substitute
for 
find the value of y in the linear equation
=120\ miles)
> is correct
case b) the speed is miles per hour
the statement is false
because the speed is 
case c) the unit rate for the trip is
the statement is true
because the speed is equal to the slope of the linear equation
case d) it took 
minutes to go the first miles
the statement is true
because
substitute
for \ hour)
find the value of y in the linear equation
=20\ miles)
> is correct
