train runs from A to B at 105 miles per hour; the other runs from B to A
at 85 miles per hour. How far apart were the two trains 30 minutes
prior to their crossing?
They were 95 miles apart 30 minutes before the two trains crossed each other.
one train is traveling at 105 MPH, and the other at 85 MPH, the
relative speed is 190 MPH (105 + 85). One hour (or 60 minutes) before
they crossed, they would have been 190 miles apart. Since the question
asked how far away they were 30 minutes before they crossed, then it
would be half that distance, or 95 miles.