Hi everyone, I am new to these forums and thought this would be a good place to get some help. I picked up a three dollar russian made math problem book at a local book sale. I am working on the questions it has in it and I came across the first problem on motion it has and I cant quite figure it out. This is high-school level stuff by the way so I would hope its easy for many here. Problem: The train left station A for station B. Having travelled 450 km, which constitues 75 percent of the distance between A and B, the train was stopped by a snow-drift. Half an hour later the track was cleared and the engine-driver, having increased the speed by 15 km per hour arrived at station B on time. Find the initial speed of the train. I have tried to visualize the problem. This is what I have come up with. Click Here The question has no total time and you have to find speed. So are there two unknowns to solve? And how do I do that in this problem? Or is there a different way to solve this? Thanks for any help.