A billiard ball travels 0.44m from its original position, bounces off another ball and travels 0.88m [N], then bounces off the edge of the billiard table coming to rest 0.12m from that edge. The entire motion is one-dimentional and takes 2.4s. (a) calculate the average speed of the ball. Okay the answer at the back of the book is 0.60 m/s. Firstly, I thought that 'average speed' is actually 'average velocity'. If that is the case then average velocity is delta d / t. If I take 0.12(d2) - 0 (d1) / 2.4 I get 0.05 m/s. Which according to the book is incorrect. The only way that I get the correct answer if it I add up all the distances (0+0.44+0.88+0.12) and divide by the time (2.4) = 0.60 m/s. I'm confused on why I should be adding up all the distances instead of taking the final distance minus the original distance, divided by the time? What am I missing here? Thanks in advance.