Tom took a trip of 1,020 miles. he traveled by train at 55 miles an hour and the same number of hours by plane at 285mph how many hours did the trip take?

D = vt

Distance traveled by train
d = 55t
Distance traveled by plane
d = 285t
Total distance
d = 1020

So, you do:
distance traveled by plane + distance traveled by train =  total distance
(55t) + (285t) = 1020

Solve for t
t = 3 hours

t is the time traveled by each so 3 hrs traveled by train and 3 hrs traveled by plane

Total time  = 3 + 3 = 6 hours