(1) The abscissa of a point in the diagram represents time, so point E is farthest from home, the abscissa represents the farthest time from home, and the ordinate represents the distance from home;

(2) Rest means that the distance does not increase with the increase of time;

(3) The fastest time to come back is to divide the distance by the time spent;

(4) Divide the distance Lingling walked by the time spent.

Solution: Observing the image, we can know that: (1) Lingling needs 3 hours to reach the farthest place from home, 30 kilometers away from home;

(2) First rest at10: 30; Rest for half an hour;

(3) Lingling is the fastest on the way back, with a speed of 30 ÷ (15-13) =15 km/h;

(4) The average riding speed of Lingling is: (30+30) ÷ (15-9) =10 km/h. 。

This problem is a basic problem of function image, and the key to solving the problem is to sort out the relevant information needed for solving the problem by carefully observing the image, so this problem is actually to test students' ability to read pictures.