What aspect of the author's theory does Professor Ladd's work attempt to verify?

The distance d that a car can travel in a certain amount of time t can be found by multiplying the rate of speed r by the travel time. if a car has already travel 4 miles, the formula for the total distance travel is d= rt + 4. which of the following gives the value of r, in terms of d and t?

Increasing line of siam top trave increasing line of sight and path of travel is good idea when driving at higher speeds because it a driver to remain prepared

Driving on the highway can lead you to the hypnosis of a road, a condition of drowsiness or ignorance, you can avoid this condition