Two trains run in opposite directions. When will the trains cross each other? How many kilometers will the trains have run? This is a classic problem in which you manage and use ratios and simple lineal equation systems.
You can find the solution of uniform movement.
The application generates random numbers to get different problems and you enter solutions that are checked if they are right.
You can enter your data to get a certain problem.
Animation provides an scale simulation of the trains movement.