Inactive Tutor answered 05/28/19
If the two trains are leaving from the same station and travelling in opposite directions, then their distances will get added together. You want to find the time t (hours) where the two distances add up to 495 miles.
Use the formula distance = rate x time to find the distance that each train travels in t hours. (Keep the variable for t, because it is the same for both trains, and it is the value the question is looking for.)
First train: d1 = r1t = 45t
Second train: d2 = r2t = 54t
Combined distance = d1+ d2 = 45t + 54t = 99t
Since you want the combined distance to be 495 miles, solve the algebraic equation to find the time t when that happens.
Hope this helps!