A car is traveling on a highway. The distance (in miles) from its destination and the time (in hours) is given by the equation d=420-65t. What is the slope of the line represented by the equation? What is the practical meaning of the slope? a. m=420; The total distance is 420 miles. b. m=65; The car is traveling 65 miles per hour. c. m=-65; The car is traveling 65 miles per hour. d. m=-420; The total distance is 355 miles.