distance time graph is a graph traveled in a graph which shows how much we have traveled in equal period of time.
So, what is the question? - Well, you would need a greater speed, to travel a longer distance in the same time.
(a distance traveled) divided by (time to travel the distance) is known as a "speed" .
"Speed" means distance traveled in some period of time/time to travel the distance .
Distance Traveled is directly proportional to velocity. This is because velocity is the change in position over a period of time. The greater the velocity, the greater the distance traveled. For you calculus junkies, integrate velocity to get displacement.
Speed = (distance traveled in some period of time) divided by (time to cover that distance)
With distance on the x axis and time on the y axis a steep line would indicate a short distance traveled over a long period of time, depending on the scale of the graph.
Rate of travel = (distance traveled) divided by (time traveled)
The object's average speed during that period of time.