Well, since there is no attached graph, I can't really help, but I can assume that the graph can be broken down into simpler shapes, which you should find the area of individually and add together to find distance. The area under a velocity-time graph is distance.

Try breaking it into squares, rectangles and triangles, OR, if they give you the equation and you know calculus (I'm assuming you do since this is in the calculus forum), take the definite integral from 0 to 30 (seconds) v(t)dt and that's your distance.