A boy runs from a point A to a point C. He pauses at C and then walks back towards A until reaching the point B, where he stops. The diagram shows the graph of v against t, where v m s^-1 is the boy’s velocity at time t seconds after leaving A. The boy runs and walks in the same straight line throughout.

(i) Find the distances AC and AB.

(ii) Sketch the graph of x against t, where x metres is the boy’s displacement from A. Show clearly the values of t and x when the boy arrives at C, when he leaves C, and when he arrives at B.