Answer:
3.64 hours
Explanation:
Let t (hours) be the time that it takes for the trains to pass each other. In this problem we will solve for t.
Then the distance the first train would cover after t hours is 90t
Likewise, the distance the 2nd train would cover after t hours is 75t
For the 2 trains to meet somewhere on the track, their total distance that they covered must be the original distance between them, which is 600 miles
So 90t + 75t = 600
165t = 600
t = 600 / 165 = 3.64 hours
