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