I'm having trouble with this problem mostly because I can't think of the logic behind it, so I don't know which of the basic formulae to use. Excuse my "noobieness" as I'm a first-year physics student. The question states, "Two trains face each other on adjacent tracks. They are initially at rest, and their front ends are 39 m apart. The train on the left accelerates rightward at 0.91 m/s^2. The train on the right accelerates leftward at 1.19 m/s^2. How far does the train on the left travel before the front ends of the trains pass?" So far, I've tried to do the problem manually by subtracting both trains' movements from the total 39m, but that is very inefficient and hard to get perfectly. Can anyone give me a push in the right direction? I feel like this should be easy, I'm just having a momentary brainfart.