Train A leaves City A at 10 am, avg speeds 200 mph. Train B leaves City B 10:20 their time, 220 mph. Tweather is clear. When will the 2 trains collide

Assuming they are both on the same track, in the same time zone and headed towards each other and that City A and City B are X miles apart and that X is at least 66.7 miles apart: They will collide at time T were X = the distance between the cities and T = (X- 66.7M)/440 MH)