Answer
It will take 2.5 hours for both trains to meet.
Work Step by Step
Since both trains leave at the same time, they will have traveled the same amount of time when they meet. Let t represent the time they travel until they meet.
The freight train travels at 40 miles per hour, for a time of t, meaning that it travels for a distance which is equal to 40 $\times$ t = 40t.
The passenger train travels at 90 miles per hour, for a time of t, which means that it travels for a distance which equals to 90 $\times$ t = 90t.
Since they both travel for a distance of 325, we can set up the following equation:
40t + 90t = 325
130t = 325
t = 2.5
It will take 2.5 hours for both trains to meet.