Question 323235
Train A is slower, but ahead of train B for the time being. Train B is catching up because it is traveling 20 mph faster.

Train B is 12 minutes behind train A. That is 1/5 hour.

Train B catches Train A when their distances are the same.

120(t-1/5)=100t

Solve for t. That is how long it takes B to catch A after they pass the station.