I understand that this is a REALLY simple question, but for the life of me, I cannot figure out how to get the right answer. "Two cars, A and B, are 400. meters apart. Car A travels due east at 30. meters per second on a collision course with car B, which travels due west at 20. meters per second. How much time elapses before the two cars collide?" Hopefully, some of you helpful souls out there can help me out. I hope no ridicule comes from this. :( What I have done is find out how much time Car A would take to travel 400 M. 400/30 = 13.333 s Now I know that they WILL collide atleast before 13.333 s. Other than that, I'm stuck. Thanks in advance.