How do you read distance-time graphs?

If the line is horizontal this means that the object is not moving.

If the line is sloped this way / then it means that the object is moving at a constant speed (the speed is staying the same) and travelling away from the starting point.

If the line is sloped this way \ then it means that the object is moving at a constant speed and travelling back towards the starting point.

To work out the speed you need to find the gradient of the line. Typically you would do this be forming a right-angled triangle between 2 points on the line. To make life easy pick 2 points that have whole number co-ordinates. Then find the height of the triangle (the change in the y direction) and the base ( the change in the x direction). The gradient is the change in the y direction (height) divided by the change in the x direction (base).

To find the distance at a given time, draw a line up from the time on the x axis to meet the graph then draw a horizontal line across to the y axis to read off the distance.