Answer:
Carrie left Colorado at 2:45pm CST on Tuesday.
Step-by-step explanation:
The train travels a total of 24 hours to get from Colorado to Illinois, that is, it takes one complete day of travel to get from one city to the other.
So, if Carrie arrives Illinois at 2:45pm CST on Wednesday, she left Colorado exactly one day before that, in the same hour, so she left Colorado at 2:45pm CST on Tuesday.