Two trains began their trip from the same station at 8: 00 a. m. one train traveled north at a rate of 44 mph and the other traveled south at a rate of 46 mph. what time will it be when the trains are 405 miles apart?

Add the two speeds together:
44 +46 = 90 miles per hour total

divide the total distance by the total speed to get total number of hours

405 / 90 = 4.5 hours

 now add that to the starting time:

8 am + 4.5 hours = 12:30 pm the trains were 405 miles apart