.
Since they move towards each other, their relative speed is the sum 45 mph + 30 mph = 75 mph.
It means that the distance between them decreases at the rate of 75 mph.
Hence, it will take = = hours = 4 hours and 36 minutes for the two trains to meet.
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For many similar solved Travel and Distance problems see the lessons
- Travel and Distance problems
- Travel and Distance problems for two bodies moving in opposite directions
- Travel and Distance problems for two bodies moving in the same direction (catching up)
in this site.